POLYMORPHISMS AND NEW GENES IN THE REGION OF THE HUMAN HEMOCHROMATOSIS GENE

Abstract: Polymorphic sites in the region surrounding the HFE gene are provided. These polymorphisms are useful as surrogate markers in diagnostic assays for hemochromatosis. Additionally, a fine structure map of the 1 megabase region surrounding the HFE gene is provided, along with 235 kb of DNA sequence and 8 loci corresponding to candidate genes within the 1 megabase region, and in the purification of related proteins.

Description: Polymorphisms and New Genes in the Region of the Human Hemochromatosis Gene BACKGROUND OF THE INVENTION Hereditary hemochromatosis (HH) is an inherited disorder of iron metabolism wherein the body accumulates excess iron In symptomatic individuals, this excess iron leads to deleteπous effects by being deposited in a vaπety of organs leading to their failure, and resulting in cirrhosis, diabetes, steπlity, and other seπous illnesses The gene which is defective in this disease was disclosed in copending U S S N 08/652,265 Fine structure mapping of the region to which the gene responsible for HH, HFE (denoted HH or HFE in some publications), was mapped makes possible the identification of candidate sequences compπsing the HFE gene, along with structural elements for regulation and expression and neighboπng genes A variety of techniques is available for fine structure mapping, including direct cDNA selection, exon-trapping, and genomic sample sequencing The direct selection approach (Lovett et al Proc Natl Acad Sci U S A 88 9628-9623 (1991 )) involves the hybπdization of cDNA fragments to genomic DNA This technique is extremely sensitive and capable of isolating portions of rare transcπpts Exon-trapping (Church et al Nature Genetics 6 98-105 (1994)) recovers spliced introns from in vivo expressed genomic DNA clones and produces candidate exons without requiπng any prior knowledge of the target's gene expression High-throughput genomic DNA sequencing with comparison of the sequence data to databases of expressed sequences has also been used, such as in the positional cloning of the Werner syndrome gene (Yu et al Science 277 258-262 (1996)) and in cloning by homology of the second Alzheimer's disease gene on chromosome 1 (Levy-Lahad et al Science 259 973-977 (1995)) HH is typically inherited as a recessive trait, in the current state of knowledge homozygotes carrying two defective copies of the gene are most frequently affected by the disease In addition, heterozygotes for the HFE gene are more susceptible to sporadic porphyπa cutanea tarda and potentially other disorders (Roberts et al , Lancet 349 321-323 (1997) It is estimated that approximately 10-15% of Caucasians carry one copy of the HFE gene mutation and that there are about one million homozygotes in the United States HH, thus, represents one of the most common genetic disease mutations in Caucasian individuals Although ultimately HH produces debilitating symptoms, the majority of homozygotes and heterozygotes have not been diagnosed The need for such diagnostics is documented, for example, in Barton, J C et al Nature Medicine 2 394-395 (1996), Finch, C A West J Med 153.323-325 (-19901, Mr.Ciisir.k V Mendelian Inheritance in Man pp 1882-1887, 1 1th ed , (Johns Hopkins University Press, Baltimore (1994)); Report of a Joint World Health Orαanization/Hemochromatosis Foundation/French Hemochromatosis Association Meeting on the Prevention and Control of Hemochromatosis (1993), Edwards, C Q et al New Enαl J Med 328'1616-1620 (1993), Bacon, B R New Enαl J Med 326 126- 127 (1992); Balan, V. et al. Gastroenteroloαv 107:453-459 (1994); Phatak, P.D. et al. Arch Int Med 154:769-776 (1994). A single mutation in the HFE gene, designated 24d1 in copending U.S.S.N. 08/630,912, gave rise to the majority of disease-causing chromosomes present in the population today. This is referred to herein as the "common" or "ancestral" or "common ancestral" mutation. These terms are used interchangeably. It appears that about 80% to 90% of all HH patients carry at least one copy of the common ancestral mutation which is closely linked to specific alleles of certain genetic markers close to this ancestral HFE gene defect. These markers are, as a first approximation, in the allelic form in which they were present at the time the ancestral HFE mutation occurred. See, for example, Simon, M. et al. Am J Hum Genet 41 :89-105 (1987); Jazwinska, E.C. et al. Am J Hum Genet 53:242-257 (1993); Jazwinska, E.C. et al. Am J Hum Genet 56:428-433 (1995); Worwood, M. et al. Brit J Hematol 86:863-866 (1994); Summers, K.M. et al. Am J Hum Genet 45:41-48 (1989). Several polymorphic markers in the HFE region have been described and shown to have alleles that are associated with HH disease. These markers include the published microsatellite markers D6S258, D6S306 (Gyapay, G. et al. Nature Genetics 7:246-339 (1994)), D6S265 (Worwood, M. et al. Brit J Hematol 86:833-846 (1994)), D6S105 (Jazwinska, E.C. et al. Am J Hum Genet 53:242-257 (1993); Jazwinska, E.C. et al. Am J Hum Genet 56:428-433 (1995)), D6S1001 (Stone, C. et al. Hum Molec Genet 3:2043-2046 (1994)), D6S1260 (Raha-Chowdhury et al. Hum Molec Genet 4:1869-1874 (1995)) as well as additional microsatellite and single-nucleotide-polymorphism markers disclosed in co-pending PCT application WO 96/06583, the disclosure of which is hereby incorporated by reference in its entirety. Additionally, copending U.S.S.N. 08/630,912 disclosed additional markers 24d2 and 24d7. The symptoms of HH are often similar to those of other conditions, and the severe effects of the disease often do not appear immediately. Accordingly, it would be desirable to provide a method to identify persons who may be destined to become symptomatic in order to intervene in time to prevent excessive tissue damage associated with iron overload. One reason for the lack of early diagnosis is the inadequacy of presently available diagnostic methods to ascertain which individuals are at risk, especially while such individuals are presymptomatic. Although blood iron parameters can be used as a screening tool, a confirmed diagnosis often employs liver biopsy which is undesirably invasive, costly, and carries a risk of mortality. Thus, there is a clear need for the development of an inexpensive and noninvasive diagnostic test for detection of homozygotes and heterozygotes in order to facilitate diagnosis in symptomatic individuals, provide presymptomatic detection to guide intervention in order to prevent organ damage, and for identification of heterozygote carriers. Furthermore, a need exists for both methods for fine structure mapping and a fine structure map of the region of the chromosome to which the HH locus maps. This and other needs are addressed by the present invention. SUMMARY OF THE INVENTION One aspect of the invention is an oligonucleotide comprising at least 8 to about 100 consecutive bases from the sequence of Figure 9, or the complement of the sequence, wherein the at least 8 to about 100 consecutive bases includes at least one polymorphic site of Table 1. Another aspect of the invention is an oligonucleotide pair selected from the sequence of Figure 9 or its complement for amplification of a polymorphic site of Table 1. Another aspect of the invention is an isolated nucleic acid molecule comprising about 100 consecutive bases to about 235 kb substantially identical to the sequence of Figure 9, wherein the DNA molecule comprises at least one polymorphic site of Table 1. Another aspect of the invention is a method to determine the presence or absence of the common hereditary hemochromatosis (HFE) gene mutation in an individual comprising: providing DNA or RNA from the individual; and assessing the DNA or RNA for the presence or absence of a haplotype of Table 1 , wherein, as a result, the absence of a haplotype of Table 1 indicates the likely absence of the HFE gene mutation in the genome of the individual and the presence of the haplotype indicates the likely presence of the HFE gene mutation in the genome of the individual. Another aspect of the invention is a method to determine the presence or absence of the common hereditary hemochromatosis (HFE) gene mutation in an individual comprising: providing DNA or RNA from the individual; and assessing the DNA or RNA for the presence or absence of a genotype defined by a polymorphic allele of Table 1 , wherein, as a result, the absence of a genotype defined by a polymorphic allele of Table 1 indicates the likely absence of the HFE gene mutation in the genome of the individual and the presence of the genotype indicates the likely presence of the HFE gene mutation in the genome of the individual. Another aspect of the invention is a culture of lymphoblastoid cells having the designation ATCC CRL-12371. One aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to BTF1. A further aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to BTF2. A further aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to BTF3. A further aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to BTF4. A further aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to BTF5. A further aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to NPT3. A further aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to NPT4. A further aspect of the invention is an isolated nucleic acid sequence comprising a nucleic acid sequence substantially identical to RoRet. Additional aspects of the invention include nucleic acid sequences that are cDNAs, polypeptides encoded by the nucleic acids of the invention and antibodies specifically immunoreactive thereto, vectors comprising the nucleic acid sequences of the invention, and hor.t cells stably transfected with the nucleic acids of the invention. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of BTF1. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of BTF2. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of BTF3. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of BTF4. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of BTF5. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of NPT3. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of NPT4. A further aspect of the invention is an isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to at least 18 contiguous nucleotides of RoRet. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a combination genetic, physical and transcription map of the HFE gene region. The first line shows the relative positions of selected genetic markers that define the HFE region. The heavy bar below represents the YAC clone used in the direct selection experiment. The order and positions of the bacterial clones employed in the exon-trapping and sample sequencing is indicated under the YAC. The thin bar under the bacterial clones represents the approximate locations of a subset of the expressed sequence fragments mapped to the contig. The thicker bars show the location of the cDNAs cloned. Two regions are bracketed; the butyrophilin family of genes (BTF), and the region where complete genomic sequencing was carried out. Figure 2 is a schematic of the 250 kb of genomic sequence including the HFE gene. Both the structure of the overall cDNA (top) and that corresponding to the coding regions (bottom), as well as the direction of transcription are shown. The positions of the histone genes, the zinc α-2 glycoprotein pseudogene, and the ESTs are also shown. Figure 3 depicts an alignment of the predicted amino acid sequence of the BTF proteins. Sequences were aligned in a pair-wise fashion using CLUSTAL W (Thompson et al. Nucl. Acids Res. 22:4673-4680) to deduce the most parsimonious arrangement. The asterisks under the alignment represent amino acids conserved in all 6 proteins; the "dots" represent conserved amino acids substitutions. Boxed are the regions within the proteins which correspond to three conserved motifs: 1) the B-G domain, 2) the transmembrane domain (TM), and 3) the B30-2 exon domain. Figure 4, panel (A) depicts a Northern blot analysis of representative members of the two groups of BTF proteins, BTF1 and BTF5. BTF1 hybridized to all tissues on the blot as a major transcript at 2.9 kb and a minor one at 5.0 kb. BTF5 hybridized to several transcripts ranging between 4.0 and 3.1 kb and as a similar expression profile to BTF1. Autoradiography was for 24 hours. The β-acti ' n hybridization demonstrated the variation in ploy (A)+ RNA between the lanes. Autoradiography was for 1 hour. In panel (B), RT-PCR analysis demonstrated that the expression of both genes was widespread. Included in the (+) lane are cDNA 21 and 44 as positive controls; the (-) lane represents the no-DNA control. Amplification using primers for the RFP gene (Isomura etal. Nucleic Acid Res. 20:5305-5310 (1992)) controlled for the integrity of the cDNA. All first strand cDNAs were checked for contaminating genomic DNA amplification by carrying out an identical experiment excluding the reverse transcriptase. In all cases, no amplification was obtained (data not shown). Figure 5(A) depicts an alignment of the predicted amino acid sequence of the RoRet gene to the 52 kD Ro/SSA auto-antigen protein. The asterisks under the alignment represent conserved amino acids; the "dots" represent conserved amino acids substitutions. The putative DNA binding cysteine-rich domain and the B30-2 exon domain are boxed. Figure 5(B) depicts an alignment of the predicted amino acid sequence of the two novel putative sodium phosphate transport proteins to that of the NPTL Figure 6, panel (A) depicts a Northern blot analysis of the RoRet gene. The RoRet cDNA hybridized to 4 different transcripts, ranging from 7.1 kb to 2.2 kb. Autoradiography was performed for 4 days. The re-hybridization of the blot with a β-actin probe showed the variation in poly (A)+ RNA between the lanes. Autoradiography was for 1 hour. Panel (B) depicts RT-PCR analysis of the RoRet gene. Included in the (+) lane was a cDNA 27 positive control. Weak amplification of the correct size was observed in the small intestine, kidney and liver. The other tissues were negative as was the no DNA control lane (-). The RFP primers demonstrated the integrity of the cDNA. Panel (C) depicts Northern blot analysis of NPT3 and NPT4. NPT3 was expressed at high abundance in the heart and muscle as a single 7.2 kb transcript. Lesser amounts were found in the other tissues. The expression pattern of NPT4 was more restricted, being found only in the liver and kidney as a smear of transcripts ranging from 2.6 to 1.7 kb. Panel (D) depicts RT-PCR analysis of the NPT3 and NPT4 genes. Included in the (+) lane were the respective CDNA22E and 22B positive controls. The NPT3 gene was expressed as the proper size PCR fragment in kidney, liver, spleen and testis. A smaller fragment was detected in all tissues with the exception of the liver. The no DNA control lane (-) was negative. NPT4 was expressed as the proper size fragment in the small intestine, kidney, liver and testis. Larger and smaller size fragments were found in all other tissues with the exception of the brain. For both genes these different size fragments may indicate alternative splice events. The no DNA control lane (-) was negative. The RFP primers demonstrated the integrity of the cDNA. Figure 7 depicts the sequences of cDNA 21 (BTF1), cDNA 29 (BTF3), cDNA 23 (BTF4), cDNA 44 (BTF5), cDNA 32 (BTF2), cDNA 27 (RoRet), cDNA 22B (NPT3), CDNA22E (NPT4). Figure 8 depicts the nucleotide sequence of approximately 235 kb in the HFE subregion from an unaffected individual Figure 9 depicts the nucleotide sequence of approximately 235 kb in the HFE subregion from an HH affected individual Polymorphic sites in the HH affected individual determined by compaπng a sequence of the corresponding region from an HH unaffected individual are listed and described in Table I DETAILED DESCRIPTION A. Definitions Abbreviations for the twenty naturally occurπng ammo acids follow conventional usage In the polypeptide notation used herein, the left-hand direction is the ammo terminal direction and the right-hand direction is the carboxyl-terminal direction, in accordance with standard usage and convention. Similarly, unless specified otherwise, the left hand end of single-stranded polynucleotide sequences is the 5' end; the left hand direction of double-stranded polynucleotide sequences is referred to as the 5' direction The direction of 5' to 3' addition of nascent RNA transcnpts is referred to as the transcπption direction, sequence regions on the DNA strand having the same sequence as the RNA and which are 5' to the 5' end of the RNA transcπpt are referred to as "upstream sequences", sequence regions on the DNA strand having the same sequence as the RNA and which are 3' to the 3' end of the RNA transcπpt are referred to as "downstream sequences" The term "nucleic acids", as used herein, refers to either DNA or RNA "Nucleic acid sequence" or "polynucleotide sequence" refers to a single- or double-stranded polymer of deoxyπbonucleotide or πbonucleotide bases read from the 5' to the 3" end It includes both self- replicating plasmids, infectious polymers of DNA or RNA and nonfunctional DNA or RNA The complement of any nucleic acid sequence of the invention is understood to be included in the definition of that sequence "Nucleic acid probes" may be DNA or RNA fragments DNA fragments can be prepared, for example, by digesting plasmid DNA, or by use of PCR, or synthesized by either the phosphoramidrte method descπbed by Beaucage and Carruthers, Tetrahedron Lett 22 1859-1862 (1981), or by the tπester method according to Matteucci, etal . J Am Chem Soc 103 3185 (1981), both incorporated herein by reference A double stranded fragment may then be obtained, if desired, by annealing the chemically synthesized single strands together under appropπate conditions or by synthesizing the complementary strand using DNA polymerase with an appropπate pπmer sequence Where a specific sequence for a nucleic acid probe is given, rt is understood that the complementary strand is also identified and included. The complementary strand will work equally well in situations where the target is a double-stranded nucleic acid The phrase "selectively hybπdizing to" refers to a nucleic acid probe that hybπdizes, duplexes or binds only to a particular target DNA or RNA sequence when the target sequences are present in a preparation of total cellular DNA or RNA "Complementary" or "target" nucleic acid sequences refer to those nucleic acid sequences which selectively hybπdize to a nucleic acid probe. Proper annealing conditions depend, for example, upon a probe's length, base composition, and the number of mismatches and their position on the probe, and must often be determined empiπcally For discussions of nucleic acid probe design and annealing conditions, see, for example, Sambrook et al Molecular Cloning a Laboratory Manual (2nd ed ), Vols 1-3, Cold Spring Harbor Laboratory, (1989) or Current Protocols in Molecular Biology. F Ausubel et al , ed Greene Publishing and Wiley- Inters ence, New York (1987) The phrase "nucleic acid sequence encoding" refers to a nucleic acid which directs the expression of a specific protein or peptide The nucleic acid sequences include both the DNA strand sequence that is transcribed into RNA and the RNA sequence that is translated into protein The nucleic acid sequences include both the full length nucleic acid sequences as well as non-full length sequences derived from the full length protein It being further understood that the sequence includes the degenerate codons of the native sequence or sequences which may be introduced to provide codon preference in a specific host cell The phrase "isolated" or "substantially pure" refers to nucleic acid preparations that lack at least one protein or nucleic acid normally associated with the nucleic acid in a host cell The phrase "expression cassette", refers to nucleotide sequences which are capable of affecting expression of a structural gene in hosts compatible with such sequences Such cassettes include at least promoters and optionally, transcription termination signals Additional factors necessary or helpful in effecting expression may also be used as described herein The term "operably linked" as used herein refers to linkage of a promoter upstream from a DNA sequence such that the promoter mediates transcπption of the DNA sequence The term "vector", refers to viral expression systems, autonomous self-replicating circular DNA (plasmids), and includes both expression and nonexpression plasmids Where a recombinant microorganism or cell culture is described as hosting an "expression vector," this includes both extrachromosomal circular DNA and DNA that has been incorporated into the host chromosome(s) Where a vector is being maintained by a host cell, the vector may either be stably replicated by the cells duπng mitosis as an autonomous structure, or is incorporated within the host's genome The term "gene" as used herein is intended to refer to a nucleic acid sequence which encodes a polypeptide This definition includes various sequence polymorphisms, mutations, and/or sequence vanants wherein such alterations do not affect the function of the gene product The term "gene" is intended to include not only coding sequences but also regulatory regions such as promoters, enhancers, and termination regions The term further includes all introns and other DNA sequences spliced from the mRNA transcπpt, along with vanants resulting from alternative splice sites The term "plasmid" refers to an autonomous circular DNA molecule capable of replication in a cell, and includes both the expression and nonexpression types Where a recombinant microorganism or cell culture is descπbed as hosting an "expression plasmid", this includes both extrachromosomal circular DNA molecules and DNA that has been incorporated into the host chromosome(s). Where a plasmid is being maintained by a host cell, the plasmid is either being stably replicated by the ceils duπng mitosis as an autonomous structure or is incorporated within the host's genome The phrase "recombinant protein" or "recombinantly produced protein" refers to a peptide or protein produced using non-native cells that do not have an endogenous copy of DNA able to express the protein. The cells produce the protein because they have been genetically altered by the introduction of the appropriate nucleic acid sequence. The recombinant pro.ein will not be found in association with proteins and other subcellular components normally associated with the cells producing the protein. The terms "protein" and "polypeptide" are used interchangeably herein. The following terms are used to describe the sequence relationships between two or more nucleic acids or polynucleotides: "reference sequence", "comparison window", "sequence identity", "percentage of sequence identity", and "substantial identity"- A "reference sequence" is a defined sequence used as a basis for a sequence comparison; a reference sequence may be a subset of a larger sequence, for example, as a segment of a full-length cDNA or gene sequence given in a sequence listing, or may comprise a complete cDNA or gene sequence. Optimal alignment of sequences for aligning a comparison window may, for example, be conducted by the local homology algorithm of Smith and Waterman Adv. APDI. Math. 2:482 (1981), by the homology alignment algorithm of Needleman and Wunsch J. Mol. Biol. 48:443 (1970), by the search for similarity method of Pearson and Lipman Proc. Natl. Acad. Sci. U.S.A. 85:2444 (1988), or by computerized implementations of these algorithms (for example, GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package Release 7.0, Genetics Computer Group, 575 Science Dr., Madison, Wl). The terms "substantial identity" or "substantial sequence identity" as applied to nucleic acid sequences and as used herein and denote a characteristic of a polynucleotide sequence, wherein the polynucleotide comprises a sequence that has at least 85 percent sequence identity, preferably at least 90 to 95 percent sequence identity, and more preferably at least 99 percent sequence identity as compared to a reference sequence over a comparison window of at least 20 nucleotide positions, frequently over a window of at least 25-50 nucleotides, wherein the percentage of sequence identity is calculated by comparing the reference sequence to the polynucleotide sequence which may include deletions or additions which total 20 percent or less of the reference sequence over the window of comparison. The reference sequence may be a subset of a larger sequence. As applied to polypeptides, the terms "substantial identity" or "substantial sequence identity" mean that two peptide sequences, when optimally aligned, such as by the programs GAP or BESTFIT using default gap weights, share at least 80 percent sequence identity, preferably at least 90 percent sequence identity, more preferably at least 95 percent sequence identity or more. "Percentage amino acid identity" or "percentage amino acid sequence identity" refers to a comparison of the amino acids of two polypeptides which, when optimally aligned, have approximately the designated percentage of the same amino acids. For example, "95% amino acid identity" refers to a comparison of the amino acids of two polypeptides which when optimally aligned have 95% amino acid identity. Preferably, residue positions which are not identical differ by conservative amino acid substitutions. For example, the substitution of amino acids having similar chemical properties such as charge or polarity are not likely to effect the properties of a protein. Examples include glutamine for asparagine or glutamic acid for aspartic acid. The phrase "substantially purified" or "isolated" when referring to a peptide or protein, means a chemical composition which is essentially free of other cellular components. It is preferably in a homogeneous state although it can be in either a dry or aqueous solution. Purity and homogeneity are typically determined using analytical chemistry techniques such as polyacrylamide gel electrophoresis or high performance liquid chromatography. A protein which is the predominant species present in a preparation is substantially purified. Generally, a substantially purified or isolated protein will comprise more than 80% of ail macromolecular species present in the preparation. Preferably, the protein is purified to represent greater than 90% of all macromolecular species present. More preferably the protein is purified to greater than 95%, and most preferably the protein is purified to essential homogeneity, wherein other macromolecular species are not detected by conventional techniques. The phrase "specifically binds to an antibody" or "specifically immunoreactive with", when referring to a protein or peptide, refers to a binding reaction which is determinative of the presence of the protein in the presence of a heterogeneous population of proteins and other biologies. Thus, under designated immunoassay conditions, the specified antibodies bind to a particular protein and do not bind in a significant amount to other proteins present in the sample. Specific binding to an antibody under such conditions may require an antibody that is selected for its specificity for a particular protein. A variety of immunoassay formats may be used to select antibodies specifically immunoreactive with a particular protein. For example, solid-phase ELISA immunoassays are routinely used to select monoclonal antibodies specifically immunoreactive with a protein. See Harlow and Lane (1988) Antibodies, a Laboratory Manual. Cold Spring Harbor Publications, New York, for a description of immunoassay formats and conditions that can be used to determine specific immunoreactivtty. As used herein, "EST" or "Expressed Sequence Tag " refers to a partial DNA or cDNA sequence of about 150 to 500, more preferably about 300, sequential nucleotides of a longer sequence obtained from a genomic or cDNA library prepared from a selected cell, cell type, tissue or tissue type, or organisms which longer sequence corresponds to an mRNA or a gene found in that library. An EST is generally DNA. One or more libraries made from a single tissue type typically provide at least 3000 different (i.e. unique) ESTs and potentially the full complement of all possible EST's representing all possible cDNAs, e.g., 50,000 - 100,000 in an animal such as a human. (See, for example, Adams et al. Scjence 252:1651-1656 (1991)). "Stringent" as used herein refers to hybridization and wash conditions of 50% formamide at 42° C. Other stringent hybridization conditions may also be selected. Generally, stringent conditions are selected to be about 5° C lower than the thermal melting point (Tm) for the specific sequence at a defined ionic strength and pH. The Tm is the temperature (under defined ionic strength and pH) at which 50% of the target sequence hybridizes to a perfectly matched probe. Typically, stringent conditions will be those in which the salt concentration is at least about 0.02 molar at pH 7 and the temperature is at least about 60°C. As other factors may significantly affect the stringency of hybridization, including, among others, base composition and size of the complementary strands, the presence of organic solvents and the extent of base mismatching, the combination of parameters is more important than the absolute measure of any one. B. Transcript Map and New Genes near HH The instant invention provides a fine structure map of the 1 megabase region surrounding the HFE gene. As part of that map the instant invention provides approximately 250 kb of DNA sequence of which about 235 kb are provided in Figure 8 and eight loci of particular interest corresponding to candidate genes within the 1 megabase region. These loci are useful as genetic and physical markers for further mapping studies. Additionally, the eight cDNA sequences corresponding to those loci are useful, for example, for the isolation of other genes in putative gene families, the identification of homologs from other species, and as probes for diagnostic assays. In particular, isolated nucleic acid sequences of at least 18 nucleotides substantially identical to contiguous nucleotides of a cDNA of the invention are useful as PCR primers. Typically, the PCR primer will be used as part of a pair of primers in a PCR reaction. Isolated nucleic acid sequences preferably comprising about 18-100 nucleotides, more preferably at least 18 nucleotides, substantially identical to contiguous nucleotides in a cDNA of the invention are useful in the design of PCR primers and probes for hybridization assays. Additionally, the proteins encoded by those cDNAs are useful in the generation of antibodies for analysis of gene expression and in diagnostic assays, and in the purification of related proteins. Thus, in one embodiment of the invention, a 235 kb sequence is provided for the HFE subregion within the 1 megabase region mapped. This sequence can serve as a reference in genetic or physical analysis of deletions, substitutions, and insertions in that region. Additionally, the sequence information provides a resource for the further identification of new genes in that region. Thus, nucleic acid sequences substantially identically to the 235 kb sequence are also included in the scope of this invention. In a further embodiment of the invention, a family of five genes, BTF1 -5, is provided which are related by sequence homology to the milk protein butyrophilin (BT) (Figures 1 , 3, and 7). The predicted amino acid sequences of the proteins encoded by these genes are provided in Figure 3. These cDNAs are useful for the identification of further members of the BT family and to study regulation of expression of this family of genes. The proteins encoded by these cDNAs can be useful in the identification and isolation of ligands for the BT protein, and in the generation of agonists or antagonists of BT function. Nucleic acid sequences substantially identically to BTF1-5 and the proteins encoded by them are also included in the scope of this invention, including allelic forms. In a further embodiment of the invention, a novel gene RoRet is provided, which is related by sequence homology to the 52 kD Ro/SSA Lupus and Sjogren's syndrome autoantigen. This sequence is especially useful in the identification of other genes that may be involved in Lupus or Sjorgen's syndrome. The protein encoded by this cDNA can be useful in the identification and isolation of ligands for the autoantigen, and in the generation of agonists or antagonists of the antigen. Nucleic acid sequences substantially identically to RoRet and the proteins encoded by them are also included in the scope of this invention. In a further embodiment of the invention, two genes, NPT3 and NPT4, with structural homology to a type 1 sodium transport gene are provided. These cDNAs and the proteins expressed by them are useful in determining the etiology of hypophosphatemia, along with being useful as probes in the identification and isolation of further members of the gene family. Nucleic acid sequences substantially identically to the NPT1-like sequences and the proteins encoded by them are also included in the scope of this invention. C. Polymorphic Markers The invention provides 397 new polymorphic sites in the region of the HFE gene. These polymorphisms are listed in Table 1. As described below, these polymorphisms were identified by comparison of the DNA sequence of an affected individual homozygous for the common ancestral HH mutation with that of an unaffected individual disclosed in copending U.S. 08/724,394. Table 1. Polymorphic Sites in the HH Region * D6S2 2 38 occurs at base 1. 24dl occurs at base 41316. D6S2239 occurs at base 84841. D6S 22 41 occurs at base 23503 2 Table 2. Polymorphic Allele Frequencies Location Frequency of ancestral variant in Frequency of unaffected variant random chromosomes in random chromosomes 219560 53% 47% 214977 65% 35% 214908 50% 50% 214795 24% 76% 214549 53% 47% 214192 65% 35% 210299 53% 47% 208862 80% 20% 208634 48% 52% 207400 25% 75% 205284 50% 50% 204341 53% 47% 202880 58% 42% 202662 98% 2% 200027 25% 75% 199030 58% 42% 198692 55% 45% 198401 55% 45% 198055 55% 45% 195693 60% 40% 195404 25% 75% 194890 55% 45% 175330 53% 47% 173948 83% 17% 173642 55% 45% 173428 80% 20% 168515 80% 20% 160007 18% 82% 149061 58% 42% 148936 82% 18% 147536 100% 0% 147021 46% 54% 141343 55% 45% 140359 55% 45% 138903 55% 45% 132569 81% 19% 125581 18% 82% 121582 80% 20% 120853 18% 82% 118874 85% 15% 115217 50% 50% 113130 40% 60% 113001 48% 52% 107858 48% 52% 103747 50% 50% 96315 25% 75% 91194 80% 20% 90088 75% 25% 89728 50% 50% 89645 50% 50% 88528 63% 37% 87892 75% 25% 87713 60% 40% 87655 50% 50% 86984 79% 21% 85705 50% 50% 85526 50% 50% Location Frequency of ancestral variant in Frequency of unaffected variant random chromosomes in random chromosomes 84638 50% 50% 84533 50% 50% 82166 78% 22% 81193 58% 42% 80189 50% 50% 78385 80% 20% 77908 88% 12% 68976 50% 50% 68259 51% 49% 66675 80% 20% 62732 50% 50% 62362 40% 60% 61653 48% 52% 61465 5% 95% 61162 60% 40% 53707 100% 0% 52875 50% 50% 52733 74% 26% 52474 47% 53% 50586 50% 50% 50553 50% 50% 50240 50% 50% 48680 53% 47% 48650 63% 37% 48440 50% 50% 47255 50% 50% 46601 53% 47% 45567 49% 51% 41316 5% 95% 40431 20% 80% 38526 23% 77% 37411 70% 30% 35983 5% 95% These polymorphisms provide surrogate markers for use in diagnostic assays to detect the likely presence of the mutations 24d1 and/or 24d2, in preferably 24d1 , in homozygotes or heterozygotes. Thus, for example, DNA or RNA from an individual is assessed for the presence or absence of a genotype defined by a polymorphic allele of Table 1 , wherein, as a result, the absence of a genotype defined by a polymorphic allele of Table 1 indicates the likely absence of the HFE gene mutation in the genome of the individual and the presence of the genotype indicates the likely presence of the HFE gene mutation in the genome of the individual. These markers may be used singly, in combination with each other, or with other polymorphic markers (such as those disclosed in co-pending PCT application WO 96/06583) in diagnostic assays for the likely presence of the HFE gene mutation in an individual. For example, any of the markers defined by the polymorphic sites of Table 1 can be used in diagnostic assays in combination with 24d1 or 24d2, or at least one of polymorphisms HHP-1 , HHP-19, or HHP-29, or microsatellite repeat alleles 19D9:205; 18B4:235; 1A2:239; 1 E4:271 ; 24E2:245; 2B8:206; 3321-1 :98; 4073-1 :182; 4440-1 :180; 4440-2:139; 731-1 :177; 5091-1 :148; 3216-1 :221 ; 4072-2:170; 950-1 :142; 950-2:164; 950-3:165; 950-4:128; 950-6:151 ; 950-8:137; 63-1 :151 ; 63-2:113; 63-3:169; 65-1 :206; 65- 2:159; 68-1 :167; 241-5:108; 241-29:113; 373-8:151 ; and 373-29:113, D6S258:199, D6S265:122, D6S105:124; D6S306:238; D6S464:206; and D6S1001 :180. Table 2 lists the frequency of about 100 of the alleles defined by the polymorphic sites of the invention in the general population. As is evident from the Table, certain of these alleles are present rarely in the general population. These polymorphisms are thus preferred as surrogate markers in diagnostic assays for the presence of a mutant HFE allele ("gene mutation") such as 24d1 or 24d2. Preferably, the frequency of the polymorphic allele used in the diagnostic assay in the general population is less than about 50%, more preferably less than about 25%, and most preferably less than about 5%. Thus, of the genotypes defined by the alleles listed in Table 2, polymorphisms occurring at base 35983 and base 61465 of Figure 1 are preferred. It will be understood by those of skill in the art that because they were identified in an ancestral HH homozygote, the haplotypes defined by the polymorphic sites of Table 1 are predictive of the likely presence of the HFE gene mutation 24d1. Thus, for example, the likelihood of any affected individual having at least two or more of any. of the polymorphic alleles defined by Table 1 is greater than that for any unaffected individual. Similarly, the likelihood of any affected individual having at least three or more of any of the polymorphic alleles defined by Table 1 is greater than that for any unaffected individual. Thus, for example, in a diagnostic assay for the likely presence of the HFE gene mutation in the genome of the individual, DNA or RNA from the individual is assessed for the presence or absence of a haplotype of Table 1 , wherein, as a result, the absence of a haplotype of Table 1 indicates the likely absence of the HFE gene mutation in the genome of the individual and the presence of the haplotype indicates the likely presence of the HFE gene mutation in the genome of the individual. The markers defined by the polymorphic sites of Table 1 are additionally useful as markers for genetic analysis of the inheritance of certain HFE alleles and other genes which occur within the chromosomal region corresponding to the sequence of Figure 9 which include, for example, those disclosed in copending U.S.S.N. 08/724,394. As the entire nucleotide sequence of the region is provided in Figure 9, it will be evident to those of ordinary skill in the art which sequences to use as primers or probes for detecting each polymorphism of interest. Thus, in some embodiments of the invention, the nucleotide sequences of the invention include at least one oligonucleotide pair selected from the sequence of Figure 9 or its complement for amplification of a polymorphic site of Table 1. Furthermore, in some embodiments of the invention a preferred hybridization probe is an oligonucleotide comprising at least 8 to about 100 consecutive bases from the sequence of Figure 9, or the complement of the sequence, wherein the at least 8 to about 100 consecutive bases includes at least one polymorphic site of Table 1. In some embodiments the polymorphic site is at base 35983 or base 61465. It will also be appreciated that the nucleic acid sequences of the invention include isolated nucleic acid molecules comprising about 100 consecutive bases to about 235 kb substantially identical to the sequence of Figure 9, wherein the DNA molecule comprises at least one polymorphic site of Table 1. Such isolated DNA sequences are useful as primers, probes, or as the component of a kit in diagnostic assays for detecting the likely presence of the HFE gene mutation in an individual. D. Nucleic Acid Based Screening Individuals carrying polymorphic alleles of the invention may be detected at either the DNA, the RNA, or the protein level using a variety of techniques that are well known in the art. The genomic DNA used for the diagnosis may be obtained from body cells, such as those present in peripheral blood, urine, saliva, bucca, surgical specimen, and autopsy specimens. The DNA may be used directly or may be amplified enzymatically in vitro through use of PCR (Saiki et al. Science 239:487-491 (1988)) or other in vitro amplification methods such as the ligase chain reaction (LCR) (Wu and Wallace Genomics 4:560-569 (1989)), strand displacement amplification (SDA) (Walker et al. Proc. Natl. Acad. Sci. U.S.A. 89:392-396 (1992)), self-sustained sequence replication (3SR) (Fahy et al. PCR Methods Aopl. 1 :25-33 (1992)), prior to mutation analysis. The methodology for preparing nucleic acids in a form that is suitable for mutation detection is well known in the art. The detection of polymorphisms in specific DNA sequences, such as in the region of the HFE gene, can be accomplished by a variety of methods including, but not limited to, restriction- fragment-length-polymorphism detection based on allele-specific restriction-endonuclease cleavage (Kan and Dozy Lancet ii:910-912 (1978)), hybridization with allele-specific oligonucleotide probes (Wallace et al. Nucl Acids Res 6:3543-3557 (1978)), including immobilized oligonucleotides (Saiki et al. Proc. Natl. Acad. Sci. U.S.A. 86:6230-6234 (1989)) or oligonucleotide arrays (Maskos and Southern Nucl Acids Res 21 :2269-2270 (1993)), allele-specific PCR (Newton et al. Nucl Acids Res 17:2503- 2516 (1989)), mismatch-repair detection (MRD) (Faham and Cox Genome Res 5:474-482 (1995)), binding of MutS protein (Wagner et al. Nucl Acids Res 23:3944-3948 (1995), denaturing-gradient gel electrophoresis (DGGE) (Fisher and Lerman et al. Proc. Natl. Acad. Sci. U.S.A. 80:1579-1583 (1983)), single-strand-conformation-polymorphism detection (Orita et al. Genomics 5:874-879 (1983)), RNAase cleavage at mismatched base-pairs (Myers et al. Science 230:1242 (1985)), chemical (Cotton et al. Proc. Natl. Acad. Sci. U.S.A. 85:4397-4401 (1988)) or enzymatic (Youil et al. Proc. Natl. Acad. Sci. U.S.A. 92:87-91 (1995)) cleavage of heteroduplex DNA, methods based on allele specific primer extension (Syvanen et al. Genomics 8:684-692 (1990)), genetic bit analysis (GBA) (Nikiforov et al. Nucl Acids Res 22:4167-4175 (1994)), the oligonucleotide-ligation assay (OLA) (Landegren et al. Science 241 :1077 (1988)), the allele-specific ligation chain reaction (LCR) (Barrany Proc. Natl. Acad. Sci. U.S.A. 88:189-193 (1991)), gap-LCR (Abravaya et al. Nucl Acids Res 23:675-682 (1995)), radioactive and/or fluorescent DNA sequencing using standard procedures well known in the art, and peptide nucleic acid (PNA) assays (Orum et al., Nucl. Acids Res. 21 :5332-5356 (1993); Thiede et al., Nucl. Acids Res. 24:983-984 (1996)). In addition to the genotypes defined by the polymorphisms of the invention, as described in co-pending PCT application WO 96/35802 published November 14, 1996, genotypes characterized by the presence of the alleles 19D9:205; 18B4:235; 1A2:239; 1E4271 ; 24E2:245; 2B8:206; 3321-1 :98 (denoted 3321-1:197 therein); 4073-1:182; 4440-1 :180; 4440-2:139; 731-1 :177; 5091-1 :148; 3216-1 :221 ; 4072-2:170 (denoted 4072-2:148 therein); 950-1 :142; 950-2:164; 950-3:165; 950-4:128; 950-6:151 ; 950-8:137; 63-1 :151 ; 63-2:113; 63-3:169; 65-1 :206; 65-2:159; 68-1 :167; 241- 5:108; 241-29:113; 373-8:151 ; and 373-29:113, alleles D6S258:199, D6S265:122, D6S105:124, D6S306:238, D6S464:206; and D6S1001 :180, and/or alleles associates with the HHP-1 , the HHP-19 or HHP-29 single base-pair polymorphisms can also be used to assist in the identification of an individual whose genome contains 24d1 and/or 24d2. For example, the assessing step can be performed by a process which comprises subjecting the DNA or RNA to amplification using oligonucleotide primers flanking a polymorphism of Table 1 , and oligonucleotides flanking 24d1 and/or 24d2, oligonucleotide primers flanking at least one of the base-pair polymorphisms HHP-1 , HHP-19, and HHP-29, oligonucleotide primers flanking at least one of the microsatellite repeat alleles, or oligonucleotide primers for any combination of polymorphisms or microsatellite repeat alleles thereof. Oligonucleotides useful in diagnostic assays are typically at least 8 consecutive nucleotides in length, and may range upwards of 18 nucleotides in length to greater than 100 or more consecutive nucleotides. Such oligonucleotides can be derived from either the genomic DNA of Figure 8 or 9, or cDNA sequences derived therefrom, or may be synthesized. Additionally, the proteins encoded by such cDNAs are useful in the generation of antibodies for analysis of gene expression and in diagnostic assays, and in the purification of related proteins. E. General Methods The nucleic acid compositions of this invention, whether RNA, cDNA, genomic DNA, or a hybrid of the various combinations, may be isolated from natural sources, including cloned DNA, or may be synthesized in vitro. The nucleic acids claimed may be present in transformed or transfected whole cells, in a transformed or transfected cell lysate, or in a partially purified or substantially pure form. Techniques for nucleic acid manipulation of the nucleic acid sequences of the invention such as subcloning nucleic acid sequences encoding polypeptides into expression vectors, labeling probes, DNA hybridization, and the like are described generally in Sambrook et al., Molecular Cloning - a Laboratory Manual (2nd E-d.), Vol. 1-3, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, (1989), which is incorporated herein by reference. This manual is hereinafter referred to as "Sambrook etal." There are various methods of isolating the nucleic acid sequences of the invention. For example, DNA is isolated from a genomic or cDNA library using labeled oligonucleotide probes having sequences complementary to the sequences disclosed herein. Such probes can be used directly in hybridization assays. Alternatively probes can be designed for use in amplification techniques such as PCR. To prepare a cDNA library, mRNA is isolated from tissue such as heart or pancreas, preferably a tissue wherein expression of the gene or gene family is likely to occur. cDNA is prepared from the mRNA and ligated into a recombinant vector. The vector is transfected into a recombinant host for propagation, screening and cloning. Methods for making and screening cDNA libraries are well known. See Gubler, U. and Hoffman, B.J. Gene 25:263-269 (1983) and Sambrook et al. For a genomic library, for example, the DNA is extracted from tissue and either mechanically sheared or enzymatically digested to yield fragments of about 12-20 kb. The fragments are then separated by gradient centrifugation from undesired sizes and are constructed in bacteriophage lambda vectors. These vectors and phage are packaged in vitro, as described in Sambrook, et al. Recombinant phage are analyzed by plaque hybridization as described in Benton and Davis, Science 196:180-182 (1977). Colony hybridization is carried out as generally described in M. Grunstein et al. Proc. Natl. Acad. Sci. USA. 72:3961-3965 (1975). DNA of interest is identified in either cDNA or genomic libraries by its ability to hybridize with nucleic acid probes, for example on Southern blots, and these DNA region?; are isolated by standard methods familiar to those of skill in the art. See Sambrook, et al. In PCR techniques, oligonucleotide primers complementary to the two 3' borders of the DNA region to be amplified are synthesized. The polymerase chain reaction is then carried out using the two primers. See PCR Protocols: a Guide to Methods and Applications (Innis, M, Gelfand, D., Sninsky, J. and White, T., eds.), Academic Press, San Diego (1990). Primers can be selected to amplify the entire regions encoding a full-length sequence of interest or to amplify smaller DNA " segments as desired. PCR can be used in a variety of protocols to isolate cDNA's encoding a sequence of interest. In these protocols, appropriate primers and probes for amplifying DNA encoding a sequence of interest are generated from analysis of the DNA sequences listed herein. Once such regions are PCR-amplified, they can be sequenced and oligonucleotide probes can be prepared from sequence obtained. Oligonucleotides for use as primers or probes are chemically synthesized according to the solid phase phosphoramidite triester method first described by Beaucage, S.L. and Carruthers, M.H., Tetrahedron Lett.. 22(20):1859-1862 (1981) using an automated synthesizer, as described in Needham-VanDevanter, D.R., et al., Nucleic Acids Res. 12:6159-6168 (1984). Purification of oligonucleotides is by either native acrylamide gel electrophoresis or by anion-exchange HPLC as described in Pearson, J.D. and Regnier, F.E., J. Chrom., 255:137-149 (1983). The sequence of the synthetic oligonucleotide can be verified using the chemical degradation method of Maxam, A.M. and Gilbert, W., in Grossman, L. and Moldave, D., eds. Academic Press, New York, Methods in Enzymology 65:499-560 (1980). 1. Expression Once DNA encoding a sequence of interest is isolated and cloned, one can express the encoded proteins in a variety of recombinantly engineered cells. It is expected that those of skill in the art are knowledgeable in the numerous expression systems available for expression of DNA encoding a sequence of interest. No attempt to describe in detail the various methods known for the expression of proteins in prokaryotes or eukaryotes is made here. In brief summary, the expression of natural or synthetic nucleic acids encoding a sequence of interest will typically be achieved by operably linking the DNA or cDNA to a promoter (which is either constitutive or inducible), followed by incorporation into an expression vector. The vectors can be suitable for replication and integration in either prokaryotes or eukaryotes. Typical expression vectors contain transcription and translation terminators, initiation sequences, and promoters useful for regulation of the expression of polynucleotide sequence of interest. To obtain high level expression of a cloned gene, it is desirable to construct expression plasmids which contain, at the minimum, a strong promoter to direct transcription, a ribosome binding site for translational initiation, and a transcriptionΛranslation terminator. The expression vectors may also comprise generic expression cassettes containing at least one independent terminator sequence, sequences permitting replication of the plasmid in both eukaryotes and prokaryotes, i.e., shuttle vectors, and selection markers for both prokaryotic and eukaryotic systems. See Sambrook et al. Examples of expression of ATP-sensitive potassium channel proteins in both prokaryotic and eukaryotic systems are described below. a. Expression in Prokaryotes A variety of procaryotic expression systems may be used to express the proteins of the invention. Examples include E. coli, Bacillus, Streptomyces, and the like. It is preferred to construct expression plasmids which contain, at the minimum, a strong promoter to direct transcription, a ribosome binding site for translational initiation, and a transcription/translation terminator. Examples of regulatory regions suitable for this purpose in E. coli are the promoter and operator region of the E. coli tryptophan biosynthetic pathway as described by Yanofsky, C, J. Bacteriol. 158:1018-1024 (1984) and the leftward promoter of phage lambda (Pλ) as described by Herskowitz, I. and Hagen, D., Ann. Rev. Genet. 14:399-445 (1980). The inclusion of selection markers in DNA vectors transformed in E. coli is also useful. Examples of such markers include genes specifying resistance to ampicillin, tetracycline, or chloramphenicol. See Sambrook et al. for details concerning selection markers for use in E. coli. To enhance proper folding of the expressed recombinant protein, during purification from E. coli, the expressed protein may first be denatured and then renatured. This can be accomplished by solubilizing the bacterially produced proteins in a chaotropic agent such as guanidine HCl and reducing all the cysteine residues with a reducing agent such as beta-mercaptoethanol. The protein is then renatured, either by slow dialysis or by gel filtration. See U.S. Patent No. 4,511 ,503. Detection of the expressed antigen is achieved by methods known in the art as radioimmunoassay, or Western blotting techniques or immunoprecipitati ' on. Purification from E. coli can be achieved following procedures such as those described in U.S. Patent No. 4,511 ,503. b. Expression in Eukaryotes A variety of eukaryotic expression systems such as yeast, insect cell lines, bird, fish, and mammalian cells, are known to those of skill in the art. As explained briefly below, a sequence of interest may be expressed in these eukaryotic systems. Synthesis of heterologous proteins in yeast is well known. Methods in Yeast Genetics. Sherman, F., etal., Cold Spring Harbor Laboratory, (1982) is a well recognized work describing the various methods available to produce the protein in yeast. Suitable vectors usually have expression control sequences, such as promoters, including 3-phosphoglycerate kinase or other glycolytic enzymes, and an origin of replication, termination sequences and the like as desired. For instance, suitable vectors are described in the literature (Botstein, etal., Gene 8:17-24 (1979); Broach, etal., Gene 8:121-133 (1979)). Two procedures are used in transforming yeast cells. In one case, yeast cells are first converted into protoplasts using zymolyase, lyticase or glusulase, followed by addition of DNA and polyethylene glycol (PEG). The PEG-treated protoplasts are then regenerated in a 3% agar medium under selective conditions. Details of this procedure are given in the papers by J.D. Beggs, Nature (London) 275:104-109 (1978); and Hinnen, a., et al., Proc. Natl. Acad. Sci. U.S.A. 75:1929-1933 (1978). The second procedure does not involve removal of the cell wall. Instead the cells are treated with lithium chloride or acetate and PEG and put on selective plates (Ito, H., etal., J. Bact. 153:163-168 (1983)). The proteins of the invention, once expressed, can be isolated from yeast by lysing the cells and applying standard protein isolation techniques to the lysates. The monitoring of the purification process can be accomplished by using Western blot techniques or radioimmunoassay or other standard immunoassay techniques. The sequences encoding the proteins of the invention can also be ligated to various expression vectors for use in transforming cell cultures of, for instance, mammalian, insect, bird or fish origin. Illustrative of cell cultures useful for the production of the polypeptides are mammalian cells. Mammalian cell systems often will be in the form of monolayers of cells although mammalian cell suspensions may also be used. A number of suitable host cell lines capable of expressing intact proteins have been developed in the art, and include the HEK293, BHK21 , and CHO cell lines, and various human cells such as COS cell lines, HeLa cells, myeloma cell lines, Jurkat cells, etc. Expression vectors for these cells can include expression control sequences, such as an origin of replication, a promoter (e.g., the CMV promoter, a HSV tk promoter or pgk (phosphoglycerate kinase) promoter), an enhancer (Queen et al. Immunol. Rev. 89:49 (1986)), and necessary processing information sites, such as ribosome binding sites, RNA splice sites, polyadenylation sites (e.g., an SV40 large T Ag poly A addition site), and transcriptional terminator sequences. Other animal cells useful for production of ATP-sensitive potassium channel proteins are available, for instance, from the American Type Culture Collection Catalogue of Cell Lines and Hybridomas (7th edition, (1992)). Appropriate vectors for expressing the proteins of the invention in insect cells are usually derived from the SF9 baculovirus. Suitable insect cell lines include mosquito larvae, silkworm, armyworm, moth and Drosophila cell lines such as a Schneider cell line (See Schneider J. Embrvol. EXP. Morphol. 27:353-365 (1987). As indicated above, the vector, e.g., a plasmid, which is used to transform the host cell, preferably contains DNA sequences to initiate transcription and sequences to control the translation of the protein. These sequences are referred to as expression control sequences. As with yeast, when higher animal host cells are employed, polyadenylation or transcription terminator sequences from known mammalian genes need to be incorporated into the vector. An example of a terminator sequence is the polyadenylation sequence from the bovine growth hormone gene. Sequences for accurate splicing of the transcript may also be included. An example of a splicing sequence is the VP1 intron from SV40 (Sprague, J. et al., J. Virol. 45: 773-781 (1983)). Additionally, gene sequences to control replication in the host cell may be incorporated into the vector such as those found in bovine papilloma virus type-vectors. Saveria-Campo, M., 1985, "Bovine Papilloma virus DNA a Eukaryotic Cloning Vector" in DNA Cloning Vol. II a Practical Approach Ed. D.M. Glover, IRL Press, Arlington, Virginia pp. 213-238. The host cells are competent or rendered competent for transformation by various means. There are several well-known methods of introducing DNA into animal ceils. These include: calcium phosphate precipitation, fusion of the recipient cells with bacterial protoplasts containing the DNA, treatment of the recipient cells with liposomes containing the DNA, DEAE dextran, electroporation and micro-injection of the DNA directly into the cells. The transformed cells are cultured by means well known in the art (Biochemical Methods in Cell Culture and Virology. Kuchler, R.J., Dowden, Hutchinson and Ross, Inc., (1977)). The expressed polypeptides are isolated from cells grown as suspensions or as monolayers. The latter are recovered by well known mechanical, chemical or enzymatic means. 2. Purification The proteins produced by recombinant DNA technology may be purified by standard techniques well known to those of skill in the art. Recombinantly produced proteins can be directly expressed or expressed as a fusion protein. The protein is then purified by a combination of cell lysis (e.g., sonication) and affinity chromatography. For fusion products, subsequent digestion of the fusion protein with an appropriate proteolytic enzyme releases the desired polypeptide. The polypeptides of this invention may be purified to substantial purity by standard techniques well known in the art, including selective precipitation with such substances as ammonium sulfate, column chromatography, immunopurification methods, and others. See, for instance, R. Scopes, Protein Purification: Princi p les and Practice. Springer-Verlag: New York (1982), incorporated herein by reference. For example, in an embodiment, antibodies may be raised to the proteins of the invention as described herein. Cell membranes are isolated from a cell line expressing the recombinant protein, the protein is extracted from the membranes and immunoprecipitated. The proteins may then be further purified by standard protein chemistry techniques as described above. 3. Antibodies As mentioned above, antibodies can also be used for the screening of polypeptide products encoded by the polymorphic nucleic acids of the invention. In addition, antibodies are useful in a variety of other contexts in accordance with the present invention. Such antibodies can be utilized for the diagnosis of HH and, in certain applications, targeting of affected tissues. Thus, in accordance with another aspect of the present invention a kit is provided that is suitable for use in screening and assaying for the presence of polypeptide products encoded by the polymorphic nucleic acids of the invention by an immunoassay through use of an antibody which specifically binds to polypeptide products encoded by the polymorphic nucleic acids of the invention in combination with a reagent for detecting the binding of the antibody to the gene product. Once hybridoma cell lines are prepared, monoclonal antibodies can be made through conventional techniques of priming mice with pristane and interperitoneally injecting such mice with the hybrid cells to enable harvesting of the monoclonal antibodies from ascites fluid. In connection with synthetic and semi-synthetic antibodies, such terms are intended to cover antibody fragments, isotype switched antibodies, humanized antibodies (mouse-human, human- mouse, and the like), hybrids, antibodies having plural specificities, fully synthetic antibody-like molecules, and the like. This invention also embraces diagnostic kits for detecting DNA or RNA comprising a polymorphism of Table 1 in tissue or blood samples which comprise nucleic acic, probes as described herein and instructional material. The kit may also contain additional components such as labeled compounds, as described herein, for identification of duplexed nucleic acids. The following examples are provided to illustrate the invention but not to limit its scope. Other variants of the invention will be readily apparent to one of ordinary skill in tie art and are encompassed by the appended claims. F. EXPERIMENTAL EXAMPLES 1. Meαabase transcript map In these studies direct selection, exon-trapping, and genomic sample sequencing were used to generate a transcript map of a 1 megabase region approximately 8.5 megabases telomeric to HLA-A in the vicinity of HFE. This region 6p21.3 was flanked by the genetic markers D6S2242 and D6S2241. The starting material for these experiments was a 1 megabase YAC labeled y899g1 and a bacterial clone contig of this region (Feder et al. Nature Genetics 13:399-408 (1996)). These techniques and other methods used in the study are outlined below. a. Direct Selection (PS) Poly A + RNA from human fetal brain, liver and small intestine (Clontech, Palo Alto, CA) were converted into cDNA using random primers and a Superscript cDNA synthesis kit (Life Technologies, Gaithersburg, MD). The cDNA was digested with Mbo I and ligated to cDNA Mbo I linker-adaptors. Unligated linker-adaptor were removed by passage through cDNA spun columns (Pharmacia, Piscataway, NJ). The 5 ng of each of the ligated cDNAs were amplified using the cDNA Mbo l-S primer (5'-CCTGATGCTCGAGTGAATTC-3'). The amplified products were purified on S-400 spin columns (Pharmacia, Piscataway, NJ), ethanol precipitated and resuspended at 1 mg/ml in TE. Gel-purified yac899g1 (Centre d'Etude du Polymorphisme Humain) was processed as described by Morgan etal. (Nucl. Acids Res. 20:5173-5179 (1992)). The cDNAs were mixed in equal molar amounts for a total of 3 mg, and blocked with a mixture of 4 mg Cot-1 DNA (Life Technologies, Gaithersburg, MD), and a cocktail of Sau 3A-digested ribosomal and five different histone DNAs. The blocked cDNAs were hybridized to biotinylated yac899g1 DNA and streptavidin capture was carried out as described by Morgan et al. (ibid). After the second round of selection, the eluted cDNAs were amplified using the cDNA Mbo l-S primer which included a (CUA)4 repeat at the 5' end to facilitate cloning into a version of pSP72 (Promega, Madison, Wl) constructed for use with uracil-DNA glycolyase cloning (UDG, Life Technologies, Gaithersburg, MD). Recombinants were transformed in DH5α, 1000 clones picked into a 96 well format, and clones prepped for DNA sequencing using AGTC boiling 96-well mini-prep system (Advance Genetic Technologies, Gaitherburg, MD). Four hundred and sixty five clones were sequenced and the resulting data searched by BLAST (Altschul etal. J. Mol. Biol. 215:403-410 (1990)). Those clones representing repetitive, bacterial, yeast, mitochondrial and histone sequences were eliminated from future considerations. The remaining sequences were then searched for overlaps and assembled into 108 unique DS contigs. The number of clones per DS contig varied between 1 to 22 with the length of each contig ranging from 250bp to 850 bp. Small sequence-tag-sites PCR assays were developed for each DS contig and two experiments were carried out concomitantly; mapping each DS contig back to the bacterial clone contig of the region and testing for the presence of each DS contig in cDNA libraries. Overall, 86 or 80% of the DS contigs mapped back to the region and were found to be in cDNA libraries. The number of 80% mapping to the region was probably an underestimate of the fidelity of the direct-selection since PCR assays which cross exon-intron boundaries would be expected to fail or give larger size products, thereby being scored negative. b. Exon-T rapping CsCI-purified genomic P1 (Genome Systems), BAC (Research Genetics) and PAC (Genome Systems) DNAs were digested with BamHI, Bgl II, Pst I Sac 1 and Xho I and 125 ng of each digest ligated into 500 ng pSPL3 (Church etal. Nature Genetics 6:98-105 (1994)) (Life Technologies, Gaithersburg, MD) digested with the appropriate restriction enzyme and phosphatased with calf intestinal alkaline phosphatase (USB, Cleveland, OH). One tenth of the ligation was used to transform XL1 -Blue MRF' cells (Stratagene, La Jolla, CA) by electroporation. Nine tenths of the electroporation was used to inoculate 10 ml of LB + 10Oμg/ml of carbenicillen and after overnight growth, DNA was prepared using Qiagen Q-20 tips (Qiagen GmbH, Hilden Germany). The remaining one tenth was plated on LB +100 μg/ml carbenicillen plates to evaluated the efficiency on cloning and to test individual clones for the present of single inserts. COS-7 cells were seed overnight at a density of 1.4 x1 OVwell in 6 well dishes. One μg of DNA was transfected using 6ml of Lipofect-Ace. Cytoplasmic RNA was isolated 48 hr post-transfection. RT-PCR was carried out as described by Church et al. (ibid) using commercially available reagents Life Technologies, Gaithersburg, MD). The resulting CUA-tailed PCR fragments for each restriction digested bacterial clone were pooled and UDG cloned into pSP72-U (a derivative of pSP72). The DNA was transformed in DH5α and the cells plated onto nylon membranes. After overnight growth, duplicates were made and the DNA hybridized to 32 P end-labeled oligos designed to detect various background products associated with the pSPL3 vector. One set of filters was hybridized with the following gel-purified oligos in 6X SSC aqueous hybridization solution at 42° C: vector-vector splicing 5'-CGACCCAGCAACCTGGAGAT-3' cryptic donor-1021 5'-AGCTCGAGCGGCCGCTGCAG-3' cryptic donor-1134 S'-AGACCCCAACCCACAAGAAG-S' The filters were washed twice in 6X SSC, 10 mM sodium pyrophosphate (NaPPi) at 60°C, 30 mins. After overnight autoradiography, non-hybridizing clones were picked and grown in 250 μl of LB + 10Oμg/ml of carbenicillin in 96 well mini-rack tubes. The samples were analyzed by PCR using the secondary PCR primers supplied in the kit (Life Technologies, Gaithersburg, MD) and those clones with inserts greater than 200 bp were selected for sequencing. Ninety-six exon traps per bacterial clone were sequenced for a total of 768 reactions and the resulting data analyzed by BLAST. In addition, each potential exon was searched against a database of the 86 DS contigs to eliminate redundant sequences. PCR assays were developed for each of the potential exons and they were tested for their presence in cDNA libraries. A total of 48 potential exons remained after these screening steps. c. Sample Seguencing A minimal set of bacterial clones chosen to cover y899g1 were prepped with the Qiagen Maxi-Prep system and purified on CsCI. Ten micrograms of DNA from each bacterial clone was sonicated in a Heat Systems Sonicator XL and end-repaired with Klenow (USB) and T4 polymerase (USB). The sheared fragments were size selected between three to four kilobases on a 0.7% agarose gel and then ligated to BstXI linkers (Invitrogen). The ligations were gel purified on a 0.7% agarose gel and cloned into a pSP72 derivative plasmid vector. The resulting plasmids were transformed into electrocompetent DH5α cells and plated on LB-carbenicillin plates. A sufficient number of colonies was picked to achieve 15-fold clone coverage. The appropriate number of colonies was calculated by the following equation to generate a single-fold sequence coverage: Number of colonies = size of bacterial clone (in kb)/average sequence read length (0.4 kb). These colonies were prepped in the 96-well AGCT system and end-sequenced with oligo MAPI using standard ABI Dye Terminator protocols. MAPI was CGTTAGAACGCGGCTACAAT. The MAPI sequences were screened locally with the BLAST algorithm against all available public databases. All sequence identities were catalogued and cross referenced to the DS and exon-trapped databases. A total of 3794 end sequence reactions were run to achieve the theoretical 1X coverage. Eighty-five percent of these sequences contained non-bacterial non-vector inserts. An additional 1060 end sequence reactions were run from the opposite end of the cloning vector to augment the sequence coverage and to prepare for contigging across selected regions. BLAST searches to all publicly available databases identified 12 histone genes and 74 unique expressed sequence fragments (ESF). The ESF represent a collection of ESTs and other expressed sequence fragments that were selected due to their sequence identity over a significant portion of genomic DNA. The ESF were cross referenced against the DS and exon-trapped databases to eliminate redundancies. 58 unique ESF remained, representing 39 distinct clones. Included in these ESF are 5 sequences homologous to histone genes. Table 3. EST's i found by Sample Sequencing Large Insert Bacterial Clones Clone name Bacterial Homology 5' Homology 3' Poly A+ Genomic cDNA clone blastx blastx signal 1 poly (A) α8 Homology EST03556 pcl57c3 na 2 none 3 + - cDNA 28 ym33fl l pcl57c3 ZNF na na na EST04698 pcl57c3 na NSH 4 + - EST04812 pcl57c3 na NSH - - yb89b08 pcl57c3 NSH na na na yd88gl l pcl57c3 na nsh + - yj49b01 pcl57c3 NSH na na na yv81d05 pcl57c3 HG17 Human NSH + - cDNA 30 yg57h09 pl96e20 BUTYBOVIN NSH + - cDNA 21 yq23d08 pl96e20 BUTYBOVIN NSH + - cDNA 21 Clone name Bacterial Homology 5' Homology 3' Poly A+ Genomic cDNA clone blastx blastx signal 1 poly (A) α8 Homology yo65f06 pl96e20 NSH na na na cDNA 29 yv88c09 pl96e20 BUTYBOVIN na na na cDNA 29 ydl7d06 pl96e20 NSH na na na cDNA 23 ye25g03 pl96e20 BUTYBOVIN NSH na na cDNA 44 ys04h08 pc45p21 NSH NSH + - cDNA 44 yn01c05 pl96e20 BUTYBOVIN na na na cDNA 32 YG78F10 PC45P21 NSH NSH na na yh54fl l pl96e20 none NSH - - ys05b08 pcl57c3 NSH Alu - + ybl2hl l bl32al2 NSH Histone H3.1 - - HSC2EE082 bl32al2 na NSH + - HUMlόOhl lb bl32al2 none na na na yg04f09 bl32bl2 Line element Alu - + J yd37dl l bl32al2 NSH Alu - + ym29g03 bl32al2 Histone H2A NSH + - cDNA 37 1 yi77b02 bl32al2 NSH NSH - - cDNA 37 yh76b05 bl32al2 NSH Alu - - yu98e02 bl32al2 NSH Alue - + yd72hl2 bl32al2 Alu NSH + + ydl9d03 pc222k22 Histone H2B.1 NSH + - ye98g01 bl32al2 NSH NSH + - cDNA yi61fl)7 bl32al2 NSH NSH - + ESTO5340 b3el7 na Alu - + yd35d05 pc222k22 NSH NSH - + yc52a05 pc75L14 NSH na na na yd84a05 pc75L14 none none - ? 5 | yr42a05 pc75L14 NaPi transport none + - CDNA 22B | yd83h08 b20h20 NSH none + - ye38c09 b20h20 NSH Alu - + yp74c05 b20h20 NaPi transport Alu ? 6 na Bracketed area is the critical region 1 Signal of AT AAA or ATTAA 4 No Significant Homologies 2 Not available 5 3 ' splice that is not on contig 3 "NONE" reported by blast 6 Poor EST sequence d. cDNA library screening Superscript plasmid cDNA libraries, brain, liver and testis, were purchased from Life Technologies, Gaithersburg, MD. Colonies were plated on Hybond N filters (Amersham) using standard techniques. Insert probes from DS, exons and EST (I.M.A.G.E. clones; Genome Systems) were all isolated by PCR followed by purification in low-melting point agarose gels (Seakem). The DNAs were labeled in gel using the Prime-it II kit (Stratagene, La Jolla, CA). Small exon probes were labeied using their respective STS PCR primers instead of random primers. Up to 5 different probes were pooled in a hybridization. Filters were hybridized in duplicate using standard techniques. Putative positives were screened by PCR using the probe's STSs to identify clones. Inserts from positive clones were subcloned in pSP72 and sequenced. e. Northern blots and RT-PCR analysis Multiple tissue northern blots were purchased from Clontech and hybridized according the manufacturer's instructions. RT-PCR was carried out on random primed first strand cDNA made from poly A+ RNA (Clontech) using AmpliTaq Gold (Perkin-Elmer). Control reactions were performed on RNA samples processed in the absence of reverse transcriptase to control for genomic DNA contamination. f. Genomic Sequencing The MAPI sequences from the bacterial clones b132a2, 222K22, and 75L14 were assembled into contigs with the Staden package (available from Roger Staden, MRC). A minimal set of 3 kb clones was selected for sequencing with oligo labeled MAP2 that sits on the opposite end of the plasmid vector. The sequence of MAP2 was GCCGATTCATTAATGCAGGT. The MAP2 sequences were entered into the Staden database in conjunction with the MAPI sequences to generate a tiling path of 3 kb clones across the region. These sequences were also screened with the BLAST algorithm and all novel sequence identities were noted. The plasmid 3 kb libraries were concurrently transformed in 96 well format into pox38UR (available from C. Martin, Lawrence Berkeley Laboratories). The transformants were subsequently mated with JGM (Strathman et al. P.N.A.S. 88:1247-1250 (1991) in 96 well format. All matings of the 3 kb clones within the tiling path were streaked on LB-carbenicillin-kanamycin plates and a random selection of 12 colonies per 3 kb clone was prepped in the AGCT system. The oligos -21 : CTGTAAAACGACGGCCAGTC, and REV: GCAGGAAACAGCTATGACC were used to sequence off both ends of the transposon. Each 3 kb clone was assembled in conjunction with the end sequence information from all bacterial clones to generate complete sequence across the region. The genomic sequence was analyzed with the BLAST nucleotide and protein homology algorithms and the GRAIL 1.2 software to identify novel open reading frames (ORF) for gene finding. q. Discussion A compilation of 174 ESF led to the construction of an expressed sequence map of the region that served as the framework for the isolation of full-length cDNAs (Figure 1). (The map shows the subset of ESF that were actually mapped). Probes were developed for 82 best ESFs which appeared to be derived from the coding portions of cDNAs and the appropriate cDNA libraries were screened. This led to the isolation of 19 cDNAs, 17 of which represented novel sequences. 70 of the 174 ESF were included in the cDNAs isolated (40%). 36 probes failed to produce any clones even after repeated screening of several libraries. 51 ESF which were not accounted for in the cDNAs cloned were not used in any screen. Therefore, it is possible that some additional genes within this 1 megabase region may have escaped detection. A list of these cDNAs cloned and a comparison of the methods used to find them is presented in Table 4. Direct selection found 14 out of the 18 cDNAs contained within the boundaries of the YAC used in the experiment. Exon trapping found 15 out of the 19 cDNAs contained within the boundaries of the large insert bacterial clone contig. Sample sequencing identified 11 genes that had corresponding ESTs in the public database. Table 4. Comparison of gene finding methods Bacterial Clone CDNA # Homology EST DS Exon Trap 157c 28 zinc finger EST03556 2 1 157c3 30 nonhistone yv81d05 1 none yvh07al0 157c3 46 ORF yd88gl l 1 157c3 20 BT none none 3 pl8696 21 BTF1 yn01G5 4 5 yg23d08 yg57h09 yul5h03 45p21 32 BTF2 yg78fl0 yn01c05 45p21 29 BTF3 ye25g03 yo65ft 6 45p21 23 BTF4 ydl7d06 4 6 45p21 44 BTF5 ys04h08 2 4 3el7 41 genomic? none none 1 132a2 43 genomic? none none 3 132a2 36 genomic? none 1 none 132a2 37 histone 2A ym29g03 3 none yh87a03 75114 24 MHC class 1 ye98g01 1 2 132a2 39 genomic? none none 4 132a2 27 Ro/SSA none 3 4 132a2 22B NPTl-like yr42a05 1 7 yf09g06 20h20 22E NPTl-like none 2 5 20h20 NPT1 NPT1 yp74c05 N/A 3 As a final approach, a tiling path with overlapping end sequences from the sample sequence database was generated. Each 3 kb clone within the path was shotgun-sequenced using transposable elements as platforms for dual end sequencing. These individual clones were assembled in conjunction with the end sequences from all bacterial clones in the region. The resulting sequence (Figure 2) was analyzed systematically with BLAST homology searches and the Grail 1.2 program to identify novel open reading frames (ORF) and other gene-like structures. The BLAST homology searches did not produce any probes that had not already been identified by sample sequencing. Grail predicted exons for ail the genes in the region, but was only able assemble the histones into any representative form. A detailed analysis of BLAST homology searches to protein databases identified an enticing homology to a zinc alpha 2 glycoprotein approximately 25 kb upstream of HFE, but the lack of a substantial ORF and the presence of a stop codon suggested that it was a pseudogene. Figure 2 shows the positions, the exon and intron structures, and the relative orientation of transcription of novel genes within this region. Also shown are the positions and transcriptional orientations of the histone genes. A total of 12 histone genes were identified in this study. In an effort to account for the ESTs that did not associate with the characterized genes in the 250 kb region, the genomic sequence around the putative 3' ends were examined for polyadenylation signals to determine whether certain EST sequences may have originated from genomic DNA contamination in the normalized cDNA libraries used in EST generation. The positions of the 14 ESTs found in this region are indicated in Figure 2 to show those associated with the cDNAs cloned and those which did not associate with genomic DNA of obvious coding potential. Four ESTs corresponded to 3 of the 4 cDNAs cloned from the region (Table 2). One EST encoded a histone H2B.1 gene and another was a repetitive element. Of the remaining 8, 6 EST clones were used as probes of cDNA libraries with negative results. Those sequences representing putative 3' ends of cDNA were searched for the presence of poly (A)+ addition signals. Five of the 13 ESTs which had 3' end sequence, had the sequence AT AAA or ATTAA. Five of the remaining 8 ESTs that did not have a poly (A)+ addition signal had genomic encoded stretches of poly (A) near the end of EST sequence and, therefore, may have been created by oligo d(T) priming of contaminating genomic DNA. This analysis was expanded to include all ESTs in the large-insert bacterial contigs with definitive 3' ends. Of the remaining 26, 15 had 3' end sequence and, of these, 8 had poly (A)+ addition signals. Five of these 8 ESTs were associated with the cloned cDNAs. Of the remaining 7 which did not have poly (A)+ addition signals, 4 had genomic encoded stretches of poly (A). i. Butyrophilin gene family The human homolog of the bovine butyrophilin gene (BT) was cloned and mapped to approximately 480 kb centromeric to HFE (Figure 1). BT is a transmembrane protein of unknown function which constitutes 40% of the total protein associated with the fat globule of bovine milk (Jack etal. J. Biol. Chem. 265:14481-14486 (1990)). A human homolog of BT has recently been cloned by Tayloer et al. (Biochem Biophvs Acta 1306:1-4 (1996)). The results in this study indicated that BT is a member of a gene family with at least five other members of the family residing in this region (Figure 1). A comparison of these proteins is shown in Figure 3. The proteins were aligned based on their descending order of relatedness and to minimized gaps in the sequence. Each of the five proteins display varying degrees of homology to BT. BTF1 (cDNA 21), BTF2 (cDNA 32), BTF5 (cDNA 44), and BTF3 (cDNA 29) are 45%, 48%, 46%, and 49%, identical to BT, whereas BTF4 (cDNA 23), which is more similar to BTF3 (cDNA 29), is only 26% identical. This low degree of identity to BT is largely due to a truncation at the carboxyl terminus of the protein. The BTF family falls into two groups: BTF1 and 2 which are more related to each other than to BT or the other BTF members, and BTF5, 3 and 4, which appear to have a common evolutionary origin. The order of these genes on the chromosome suggests that the BT gene has duplicated two times, giving rise to BTF1 and BTF5. Subsequently, it appears likely these two genes experienced further duplication events to give rise to the other members in their groups. The three major components of BT, the B-G immunoglobulin superfamily domain (containing the V consensus sequence) (Miller et al. Proc. Natl. Acad. Sci. U.S.A. 88:4377-4381 (1991)), the transmembrane region, and the B30-2 exon are found in all of these proteins (with the exception of BTF4 (cDNA 23) which lacks the B30-2 exon by virtue of the carboxyl terminal truncation). The exon B30-2 is a previously noted feature of the MHC class 1 region found approximately 200 kb centromeric to the HLA-A gene (Vernet et al., J. Mol. Evol. 37:600-612 (1993)). In addition this exon is found in several genes of diverse function telomeric to HLA-A namely MOG (approximately 200 kb) and RFP (approximately 1 megabase) (Amadou etal. Genomics 26:9-20 (1995)). The levels of the BTF mRNA were analyzed by northern blot analysis (Figure 4A). The expression of the BTF genes fell into two patterns. BTF1 and BTF2 were expressed as a single major transcript of 2.9 kb and one minor transcript of 5.0 kb. These genes were expressed at high levels in all the tissues tested with the exception of the kidney where the expression level was less. The two genes are 90% identical at the DNA sequence level, therefore, it is possible that the signal observed on the northerns was the result of cross-hybridization and only one of the two genes was actually expressed. To address this possibility RT-PCR experiments were carried out on a panel of different tissues in order to detect possible tissue dependent expression that would suggest that both genes are expressed. Identical, and thus equivocal, results were obtained with both BTF1 and BTF2 amplification (Figure 4B). The second group of genes, BTF3-5, are expressed as three (BTF5) (Figure 4A) and two (BTF3 and 4) transcripts ranging from 4.0 to 3.3 kb. BTF5 is expressed at moderate levels in all tissues tested with the exception of the kidney where the expression level is less. RT-PCR experiments showed that mRNA from the BTF5 gene can be found in all tissues tested, including the kidney (Figure 4B). Identical results were obtained with primers from the other genes of this group (data not shown). These genes are also 90% identical to each other at the DNA sequence level (but only 58% identical to BTF1 and 2), hence like BTF1 and BTF2, cross-hybridization could account for the similarity in size and patterns on the northern blots and RT-PCR. This might be particularly true for BTF4 which lacks the B30-2 exon but still hybridizes to larger size transcripts like BTF5 and BTF3. ii. A αene with similarity to 52 kD Ro/SSA auto-antioen Located approximately 120 kb telomeric to the HFE gene is a gene, RoRet, that has 58% amino acid similarity to the 52 kD Ro/SSA protein, an auto-antigen of unknown function that is frequently recognized by antibodies in patients with systemic lupus and Sjogren's syndrome (Anderson et al. Lancet 2:456-560 (1961); Clark et al. J. Immunol. 102:117-122 (1969)) (Figures 1 and 2). Alignment of the predicted amino acid sequence of this cDNA with that of 52 kD Ro/SSA indicated two features associated with the 52 kD Ro/SSA protein: a putative DNA binding cysteine rich motif (C-X-(l,V)-C-X(11-30)-C-X-H-X-(F,l,L)-C-X(2)-C-(l,L,M)-X(10-18)-C-P-X-C) found at the N terminus (Freemont et al. Cell 64: 483-484 (1991 )) and the B30-2 exon found near the carboxyl terminus, are both conserved in RoRet (Figure 5). Northern blot analysis indicated the RoRet gene was expressed as two major transcripts of 2.8 and 2.2 kb and two minor transcripts of 7.1 and 4.4 kb in all of the tissues on the blot at levels reflective of the RNA amounts as determined by β-a ;tin probing (Figure 6A). Using RT-PCR, expression can also be detected in small intestine, kidney liver, and spleen (Figure 6B). iii. Two genes with homology to a sodium phosphate transporter A cDNA for a sodium phosphate transport protein (NPT1) was previously cloned and mapped to 6p21.3 using a somatic cell hybrid panel (Chong etal. Genomics 18:355-359 (1993)). NPT1 maps 320 kb telomeric to the HFE gene (Figures 1 and 2). Two additional cDNAs were cloned which show appreciable homology to NPT1 (Figure 5). These genes, NPT3 and NPT4, mapped 1.5 megabases and 1.3 megabases centromeric to the NPT1 gene (Figure 1). Like NPT1 , the gene products of NPT3 and NPT4 were extremely hydrophobic, which may reflect a membrane location. Both proteins gave hydrophilicity profiles which were indistinguishable from NPT1 in this study (data not shown). Northern blot analysis indicated that the two genes have different patterns of expression (Figure 6C). NPT3 was expressed at high levels as a 7.2 kb transcript predominately in muscle and heart. Lesser amount of the mRNA were also found in brain, placenta, lung, liver and pancreas. RT-PCR analysis indicated that expression of the proper size PCR fragment for NPT3 was clearly absent in fetal brain, bone marrow and small intestine (Figure 6D). A smaller size fragment was detectable in all tissues with the exception of the liver, which may represent evidence for alternative splicing. Although expression was apparently absent from the kidney by northern blot analysis, it was detectable by RT-PCR. Expression was also noted in the mammary gland, spleen and testis. NPT4, on the other hand, was expressed only in the liver and the kidney as a smear of transcripts approximately 2.6 - 1.7 kb (Figure 6C). RT-PCR confirmed these results, although a small amount of the proper size PCR fragment was also found in the small intestine and testis (Figure 6D). Other tissues showed amplification, but the fragments were of larger and smaller size than that produced by the cDNA 22E positive control. Hence, these two genes which apparently have the structural characteristics of a sodium phosphate transporter, appeared to be under the control of different regulatory mechanism that lead to differential patterns of expression. 2. Sequencing of 235 kb from a Homozygous Ancestral (Affected) Individual In these studies the entire genomic sequence was determined from an HH affected individual for a region corresponding to a 235,033 bp region surrounding the HFE gene between the flanking markers D6S2238 and D6S2241. The sequence was derived from a human lymphoblastoid cell line, HC14, that is homozygous for the ancestral HH mutation and region. The sequence from the ancestral chromosome (Figure 9) was compared to the sequence of the region in an unaffected individual (Figure 8) disclosed in copending U.S.S.N. 08/724,394 to identify polymorphic sites. A subset of the polymorphic alleles so defined were further studied to determine their frequency in a collection of random individuals. The cell line HC14 was deposited with the ATCC om June 25, 1997, and is designated ATCC CRL-12371. a. Cosmid Library Screening The strategy and methodology for sequencing the genomic DNA for the affected individual was essentially as described in copending U.S.S.N. 08/724,394, hereby incorporated by reference in its entirety. Basically, a cosmid library was constructed using high molecular weight DNA from HC14 cells. The library was constructed in the supercos vector (Stratagene, La Jolla, CA). Colonies were replicated onto Biotrans nylon filters (ICN) using standard techniques. Probes from genomic subclones used in the generation of the sequence of the unaffected sequence disclosed in 08/724,394 were isolated by gel electrophoresis and electroporation. Subclones were chosen at a spacing of approximately 20 kb throughout the 235 kb region. The DNA was labeled by incorporation of 32P dCTP by the random primer labeling approach. Positively hybridizing clones were isolated to purity by a secondary screening step. Cosmid insert ends were sequenced to determine whether full coverage had been obtained, and which clones formed a minimal path of cosmids through the 235 kb region. b. Sample Sequencing A minimal set of cosmid clones chosen to cover the 235 kb region were prepped with the Qiagen Maxi-Prep system. Ten micrograms of DNA from each cosmid preparation were sonicated in a Heat Systems Sonicator XL and end-repaired with Klenow (USB) and T4 DNA polymerase (USB). The sheared fragments were size selected between three to four kilobases on a 0.7% agarose gel and then ligated to BstXI linkers (Invitrogen). The ligations were gel purified on a 0.7% agarose gel and cloned into a pSP72 derivative plasmid vector. The resulting plasmids were transformed into eiectrocompetent DH5α cells and plated on LB-carbenicillin plates. A sufficient number of colonies was picked to achieve 15-fold clone coverage. The appropriate number of colonies was calculated by the following equation to generate a single-fold sequence coverage: Number of colonies = size of bacterial clone (in kb)/average sequence read length (0.4 kb). These colonies were prepped in the 96-well Qiagen REAL, and the 5' to 3' DNA Prep Kit, and AGCT end-sequenced with oligo MAPI using standard ABI Dye Terminator protocols. MAPI was CGTTAGAACGCGGCTACAAT. c. Genomic Sequencing The MAPI sequences from the cosmid clones HC182, HC187, HC189, HC195, HC199, HC200, HC201 , HC206, HC207, and HC212 were assembled into contigs with the Staden package (available from Roger Staden, MRC). A minimal set of 3 kb clones was selected for sequencing with oligo labeled MAP2 that sits on the opposite end of the plasmid vector. The sequence of MAP2 was GCCGATTCATTAATGCAGGT. The MAP2 sequences were entered into the Staden database in conjunction with the MAPI sequences to generate a tiling path of 3 kb clones across the region. The plasmid 3 kb libraries were concurrently transformed in 96 well format into pox38UR (available from C. Martin, Lawrence Berkeley Laboratories). The transformants were subsequently mated with JGM (Strathman et al. P.N.A.S. 88:1247-1250 (1991) in 96 well format. All matings of the 3 kb clones within the tiling path were streaked on LB-carbenicillin-kanamycin plates and a random selection of 12 colonies per 3 kb clone was prepped in the AGCT system. The oligos -21 : CTGTAAAACGACGGCCAGTC, and REV: GCAGGAAACAGCTATGACC were used to sequence off both ends of the transposon. Each 3 kb clone was assembled in conjunction with the end sequence information from all cosmid clones in the region. In some regions, the coverage of the genomic sequence by cosmids was incomplete. Any gaps in the sequence were filled by using standard PCR techniques to amplify genomic DNA in those regions and standard ABI dye terminator chemistry to sequence the amplification products. d. Identification of Polymorphic Sites The assembled sequence of the cosmid clones in connection with the PCR amplified genomic DNA was compared to the genomic sequence of the unaffected individual using the FASTA algorithm. Numeric values were assigned to the sequenced regions of 1 to 235,303, wherein base 1 refers to the first C in the CA repeat of D6S2238 and base 235,303 is the last T in the GT repeat of D6S2241 of the unaffected sequence (Figure 8). Table 1 lists the differences between the two compared sequences. Note that previously disclosed (Feder et al.. Nature Genetics 13:399-408 (1996)) polymorphic sites D6S2238 (base 1), D6S2241 (base 235,032), 24d1 (base 41316), and D6S2239 (base 84841) are not included in the list of new polymorphisms, although they are provided for reference in a footnote to the Table and were observed in the ancestral sequence. In the Table, a single base change such as C-T refers to a C in the unaffected sequence at the indicated base position that occurred as a T in the corresponding position in the affected sequence. Similarly, an insertion of one or more bases, such as TTT in the affected sequence, is represented as "TTT INS" between the indicated bases of the unaffected sequence. A deletion of one or more bases occurring in the affected sequence, such as AAA DEL, is represented as the deletion of the indicated bases in the unaffected sequence. e. Characterization of Rare Polymorphisms In this study about 100 of the polymorphisms of Table 1 were arbitrarily chosen for further characterization. Allele frequencies in the general population were estimated by OLA analysis using a population of random DNAs (the "CEPH" collection, J. Dausset et al., Genomics 6(3):575-577 (1990)). These results are provided in Table 2. One single base pair difference, occurring at base 35983 and designated C182.1G7T/C (an A to G change on the opposite strand) was present in the ancestral chromosome and rare in the random DNAs. This change occurred in a noncoding region of the hemochromatosis gene near exon 7 approximately 5.3 kb from the 24d1 (Cys282Tyr) mutation. OLA was used to genotype 90 hemochromatosis patients for the C182.1G7T/C base pair change. The frequency for C occurring at this position in the patients was 79.4% as compared to 5% in the random DNAs. Eighty-five of the 90 patients assayed contained identical 24d1 and C182.1G7T/C genotypes. Four of the remaining 5 patients were homozygous at 24d1 and heterozygous at C182.1G7T/C; one was heterozygous at 24d1 and homozygous at C182.1 G7T/C. The primers used for this analysis were as follows. PCR primers for detection: 182.1 G7.F 5'-GCATCAGCGATTAACTTCTAC -3' 182.1 G7.R 5'-TTGCATTGTGGTGAAATCAGGG -3' For the detection assay, the biotinylated primers used were as follows. 182.1G7.C 5' (b)CTGAGTAATTGTTTAAGGTGC -3' 182.1 G7.T 5' (b)CTGAGTAATTGTTTAAGGTGT -3' The phosphorylated digoxigenin-labeled primer used was: 182.1 G7.D 5' (p)AGAAGAGATAGATATGGTGG -3' A further rare single base pair change was detected at 61 ,465bp. The inheritance pattern of this polymorphism, C195.1 H5C/T (a G to A change on the opposite strand), is identical to that of 24d1. The frequency of T occurring at that position (C195.1 H5T) observed in a set of 76 patients was 78.5% as compared to 5% in random individuals. PCR primers for detection: 1951 H5.3F 5 '-GAATGTGACCGTCCCATGAG-3' 1951 H5.3R 5'-CAACTGAATATGCAGAAAAAAGTACACC-3' For the detection assay, the biotinylated primers used were: 1951 H5.3.4 5' (b)AGTAGCTGGGACTCACGGTGT-3' 1957H5.3.5 5 * (b)AGTAGCTGGGACTCACGGTGC-3' The phosphorylated digoxigenin-labeled primer used was: 1951 H5.3.6 5' (p)GCGCCACCACTCCCAGCTCAT-3' These rare alleles are thus preferred surrogate markers for 24d1 and are especially useful in screening assays for the likely presence of 24d1 and/or 24d2. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety.

Claims: WHAT IS CLAIMED IS: 1. An oligonucleotide comprising at least 8 to about 100 consecu + ive bases from the sequence of Figure 9, or the complement of the sequence, wherein the at least 8 to about 100 consecutive bases includes at least one polymorphic site of Table 1. 2. The oligonucleotide of claim 1 , wherein the polymorphic site is selected from the group consisting of base 35983 or base 61465. 3. An oligonucleotide pair selected from the sequence of Figure 9 or its complement for amplification of a polymorphic site of Table 1. 4. An isolated nucleic acid molecule comprising about 100 consecutive bases to about 235 kb substantially identical to the sequence of Figure 9, wherein the DNA molecule comprises at least one polymorphic site of Table 1. 5. The isolated nucleic acid molecule of claim 4, wherein the polymorphic site is selected from the group consisting of base 35983 or base 61465. 6. The isolated nucleic acid molecule of claim 4, wherein the nucleic acid is selected from the group consisting of cDNA, RNA, or genomic DNA. 7. A polypeptide encoded by the nucleic acid molecule of claim 4. 8. An antibody which specifically recognizes the polypeptide of claim 7. 9. A method to determine the presence or absence of the common hereditary hemochromatosis (HFE) gene mutation in an individual comprising: providing DNA or RNA from the individual; and assessing the DNA or RNA for the presence or absence of a haplotype of Table 1 , wherein, as a result, the absence of a haplotype of Table 1 indicates the likely absence of the HFE gene mutation in the genome of the individual and the presence of the haplotype indicates the likely presence of the HFE gene mutation in the genome of the individual. 10. The method of claim 9, wherein the method further comprises assessing the RNA or DNA for the presence of at least one of the polymorphisms 24d1 , 24d2, HHP-1 , HHP-19, or HHP-29; or microsatellite repeat alleles 19D9:205, 18B4:235, 1A2:239, 1 E4:271 , 24E2:245, 2B8:206, 3321- 1 :98, 4073-1 :182, 4440-1 :180, 4440-2:139, 731-1 :177, 5091 -1 :148, 3216-1 :221 , 4072-2:170, 950- 1 :142, 950-2:164, 950-3:165, 950-4:128, 950-6:151 , 950-8:137, 63-1 :151 , 63-2:113, 63-3:169, 65- 1 :206, 65-2:159, 68-1 :167, 241-5:108, 241-29:113, 373-8:151 , 373-29:113, D6S258:199, D6S265:122, D6S105:124, D6S306:238, D6S464:206, or D6S1001 :180. 11. The method of claim 9, wherein the haplotype comprises at least two polymorphic sites of Table 1. 12. The method of claim 11 , wherein one of the at least two polymorphic sites of Table 1 is at base 35983 or 61465. 13. The method of claim 11 , wherein the haplotype comprises at least three polymorphic sites of Table 1. 14. A method to determine the presence or absence of the common hereditary hemochromatosis (HFE) gene mutation in an individual comprising: providing DNA or RNA from the individual; and assessing the DNA or RNA for the presence or absence of a genotype defined by a polymorphic allele of Table 1 , wherein, as a result, the absence of a genotype defined by a polymorphic allele of Table 1 indicates the likely absence of the HFE gene mutation in the genome of the individual and the presence of the genotype indicates the likely presence of the HFE gene mutation in the genome of the individual. 15. The method of claim 15, wherein the polymorphic allele occurs in less than about 50% of a random population of individuals. 16. The method of claim 15, wherein the polymorphic allele occurs in less than about 25% of a random population of individuals. 17. The method of claim 15, wherein the polymorphic allele occurs in less than about 5% of a random population of individuals. 18. The method of claim 15, wherein the genotype is C182.1 G7C or C195.1 H5T. 19. A kit comprising one or more oligonucleotides of claim 1. 20. A kit comprising at least one oligonucleotide pair of claim 3. 21. A culture of lymphoblastoid cells having the designation ATCC CRL-12371. 22. An isolated nucleic acid sequence comprising a sequence substantially identical to BTF1. 23. The isolated nucleic acid sequence of claim 23, wherein the nucleic acid is cDNA. 24. The polypeptide encoded by the isolated nucleic acid sequence of claim 23. 25. A vector comprising the nucleic acid sequence of claim 23. 26. A host cell stably transfected with the nucleic acid sequence of claim 23. 27. An antibody that is specifically immunoreactive with the polypeptide of claim 24. 28. An isolated nucleic acid sequence comprising a sequence substantially identical to BTF2. 29. The isolated nucleic acid sequence of claim 28, wherein the nucleic acid is cDNA. 30. The polypeptide encoded by the isolated nucleic acid sequence of claim 28. 31. A vector comprising the nucleic acid sequence of claim 28. 32. A host cell stably transfected with the nucleic acid sequence of claim 28. 33. An antibody that is specifically immunoreactive with the polypeptide of claim 30. 34. An isolated nucleic acid sequence comprising a sequence substantially identical to BTF3. 35. The isolated nucleic acid sequence of claim 34, wherein the nucleic acid is cDNA. 36. The polypeptide encoded by the isolated nucleic acid sequence of claim 34. 37. A vector comprising the nucleic acid sequence of claim 34. 38. A host cell stably transfected with the nucleic acid sequence of claim 34. 39. An antibody that is specifically immunoreactive with the polypeptide of claim 36. 40. An isolated nucleic acid sequence comprising a sequence substantially identical to BTF4. 41. The isolated nucleic acid sequence of claim 40, wherein the nucleic acid is cDNA. 42. The polypeptide encoded by the isolated nucleic acid sequence of claim 40. 43. A vector comprising the nucleic acid sequence of claim 40. 44. A host cell stably transfected with the nucleic acid sequence of claim 40. 45. An antibody that is specifically immunoreactive with the polypeptide of claim 42. 46. An isolated nucleic acid sequence comprising a sequence substantially identical to BTF5. 47. The isolated nucleic acid sequence of claim 46, wherein the nucleic acid is cDNA. 48. The polypeptide encoded by the isolated nucleic acid sequence of claim 46. 49. A vector comprising the nucleic acid sequence of claim 46. 50. A host cell stably transfected with the nucleic acid sequence of claim 46. 51. An antibody that is specifically immunoreactive with the polypeptide of claim 48. 52. An isolated nucleic acid sequence comprising a sequence substantially identical to NTP-3. 53. The isolated nucleic acid sequence of claim 52, wherein the nucleic acid is cDNA. 54. The polypeptide encoded by the isolated nucleic acid sequence of claim 52. 55. A vector comprising the nucleic acid sequence of claim 52. 56. A host cell stably transfected with the nucleic acid sequence of claim 52. 57. An antibody that is specifically immunoreactive with the polypeptide of claim 54. 58. An isolated nucleic acid sequence comprising a sequence substantially identical to NTP-4. 59. The isolated nucleic acid sequence of claim 58, wherein the nu ;leic acid is cDNA. 60. The polypeptide encoded by the isolated nucleic acid sequence of claim 58. 61. A vector comprising the nucleic acid sequence of claim 58. 62. A host cell stably transfected with the nucleic acid sequence of claim 58. 63. An antibody that is specifically immunoreactive with the polypeptide of claim 60. 64. An isolated nucleic acid sequence comprising a sequence substantially identical to RoRet. 65. The isolated nucleic acid sequence of claim 64, wherein the nucleic acid is cDNA. 66. The polypeptide encoded by the isolated nucleic acid sequence of claim 64. 67. A vector comprising the nucleic acid sequence of claim 64. 68. A host cell stably transfected with the nucleic acid sequence of claim 64. 69. An antibody that is specifically immunoreactive with the polypeptide of claim 66. 70. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of BTF1. 71. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of BTF2. 72. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of BTF3. 73. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of BTF4. 74. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of BTF5. 75. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of NPT3. 76. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of NPT4. 77. An isolated nucleic acid sequence comprising at least 18 contiguous nucleotides substantially identical to 18 contiguous nucleotides of RoRet.

Inventors: FEDER JOHN N, KRONMAL GREGORY S, LAUER PETER M, RUDDY DAVID A, THOMAS WINSTON J, TSUCHIHASHI ZENTA, WOLFF ROGER K, FEDER, JOHN, N., KRONMAL, GREGORY, S., LAUER, PETER, M., RUDDY, DAVID, A., THOMAS, WINSTON, J., TSUCHIHASHI, ZENTA, WOLFF, ROGER, K.
Applicants: PROGENTIOR INC, PROGENTIOR, INC.
Application year: 1997
Main classification: C07H21
IPC codes: C07K14, C07K16, C12N1, C12N5, C12N15, C12Q1