Abstract:
The invention features a method of diagnosing an iron disorder, e.g., hemochromatosis, or a genetic susceptibility to developing such a disorder in a mammal by determining the presence of a mutation in exon 2 or in an intron of an HFE nucleic acid.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     Hemochromatosis is the most common progressive (and sometimes fatal) genetic disease in people of European descent. Hemochromatosis is a disease state characterized by an inappropriate increase in intestinal iron absorption. The increase can result in deposition of iron in organs such as the liver, pancreas, heart, and pituitary. Such iron deposition can lead to tissue damage and functional impairment of the organs.  
         [0002]     In some populations, 60-100% of cases are attributable to homozygosity for a missense mutation at C282Y in the Histocompatibility iron (Fe) loading (HFE) gene, a major histocompatibility (MHC) non-classical class I gene located on chromosome 6p. Some patients are compound heterozygotes for C282Y and another mutation at H63D.  
       SUMMARY OF THE INVENTION  
       [0003]     The invention is based on the discovery of novel mutations which are associated with aberrant iron metabolims, absorption, or storage, or in advanced cases, clinical hemochromatosis. Accordingly, the invention features a method of diagnosing an iron disorder, e.g., hemochromatosis or a genetic susceptibility to developing such a disorder, in a mammal by determining the presence of a mutation in exon 2 of an HFE nucleic acid. The mutation is not a C→G missense mutation at position 187 of SEQ ID NO:1 which leads to a H63D substitution. The nucleic acid is an RNA or DNA molecule in a biological sample taken from the mammal, e.g. a human patient, to be tested. The presence of the mutation is indicative of the disorder or a genetic susceptibility to developing it. An iron disorder is characterized by an aberrant serum iron level, ferritin level, or percent saturation of transferrin compared to the level associated with a normal control individual. An iron overload disorder is characterized by abnormally high iron absorption compared to a normal control individual. Clinical hemochromatosis is defined by an elevated fasting transferrin saturation level of greater than 45% saturation.  
         [0004]     For example, the mutation is a missense mutation at nucleotide 314 of SEQ ID NO:1 such as 314C which leads to the expression of mutant HFE gene product with amino acid substitution I105T. The I105T mutation is located in the α1 helix of the HFE protein and participates in a hydrophobic pocket (the “F” pocket). The alpha helix structure of the α1 domain spans residues S80 to N 108 , inclusive. The I105T mutation is associated with an iron overload disorder.  
                         TABLE 1                       Human HFE cDNA sequence                                 atgggcccg cgagccaggc           cggcgcttct cctcctgatg cttttgcaga ccgcggtcct gcaggggcgc ttgctgcgtt       cacactctct gcaccacctc ttcatgggtg cctcagagca ggaccttggt ctttccttgt       ttgaagcttt gggctacgtg gatgaccagc tgttcgtgtt ctatgat cat  gag agt cgcc                                                          H63D   S65C       gtgtggagcc ccgaactcca tgggtttcca gtagaatttc aagccagatg tggctgcagc       tgagtcagag tctgaaa ggg  tgggatcaca tgttcactgt tgacttctgg act att atgg                         G93R                                    I105T       aaaatcacaa ccacagcaag gagtcccaca ccctgcaggt catcctgggc tgtgaaatgc       aagaagacaa cagtaccgag ggctactgga agtacgggta tgatgggcag gaccaccttg       aattctgccc tgacacactg gattggagag cagcagaacc cagggcctgg cccaccaagc       tggagtggga aaggcacaag attcgggcca ggcagaacag ggcctacctg gagagggact       gccctgcaca gctgcagcag ttgctggagc tggggagagg tgttttggac caacaagtgc       ctcctttggt gaaggtgaca catcatgtga cctcttcagt gaccactcta cggtgtcggg       ccttgaacta ctacccccag aacatcacca tgaagtggct gaaggataag cagccaatgg       atgccaagga gttcgaacct aaagacgtat tgcccaatgg ggatgggacc taccagggct       ggataacctt ggctgtaccc cctggggaag agcagagata tacgtgccag gtggagcacc       caggcctgga tcagcccctc attgtgatct gggagccctc accgtctggc accctagtca       ttggagtcat cagtggaatt gctgtttttg tcgtcatctt gttcattgga attttgttca       taatattaag gaagaggcag ggttcaagag gagccatggg gcactacgtc ttagctgaac       gtgagtgaca cgcagcctgc agactcactg tgggaaggag acaaaactag agactcaaag       agggagtgca tttatgagct cttcatgttt caggagagag ttgaacctaa acatagaaat       tgcctgacga actccttgat tttagccttc tctgttcatt tcctcaaaaa gatttcccca       tttaggtttc tgagttcctg catgccggtg atccctagct gtgacctctc ccctggaact       gtctctcatg aacctcaagc tgcatctaga ggcttccttc atttcctccg tcacctcaga       gacatacacc tatgtcattt catttcctat ttttggaaga ggactcctta aatttggggg       acttacatga ttcattttaa catctgagaa aagctttgaa ccctgggacg tggctagtca       taaccttacc agattcttac acatgtatct atgcattttc tggacccgtt caacttttcc       tttgaatcct ctctctgtgt tacccagtaa ctcatctgtc accaagcctt ggggattctt       ccatctgatt gtgatgtgag ttgcacagct atgaaggctg tgcactgcac gaatggaaga       ggcacctgtc ccagaaaaag catcatggct atctgtgggt agtatgatgg gtgtttttag       caggtaggag gcaaatatct tgaaaggggt tgtgaagagg tgttttttct aattggcatg       aaggtgtcat acagatttgc aaagtttaat ggtgccttca tttgggatgc tactctagta       ttccagacct gaagaatcac aataattttc tacctggtct ctccttgttc tgataatgaa       aattatgata aggatgataa aagcacttac ttcgtgtccg actcttctga gcacctactt       acatgcatta ctgcatgcac ttcttacaat aattctatga gataggtact attatcccca       tttctttttt aaatgaagaa agtgaagtag gccgggcacg gtggctcgcg cctgtggtcc       cagggtgctg agattgcagg tgtgagccac cctgcccagc cgtcaaaaga gtcttaatat       atatatccag atggcatgtg tttactttat gttactacat gcacttggct gcataaatgt       ggtacaacca ttctgtcttg aagggcaggt gcttcaggat accatataca gctcagaagt       ttcttcttta ggcattaaat tttagcaaag atatctcatc tcttctttta aaccattttc       tttttttgtg gttagaaaag ttatgtagaa aaaagtaaat gtgatttacg ctcattgtag       aaaagctata aaatgaatac aattaaagct gttatttaat tagccagtga aaaactatta       acaacttgtc tattacctgt tagtattatt gttgcattaa aaatgcatat actttaacaa       atgtacactg tattgtaaaa aaaaaaa       (SEQ ID NO:1; GENBANK ® Accession No. U60319)                  
 
         [0005]                              TABLE 2                       Human HFE gene product                                MGPRARPALLLLMLLQTAVLQG             RLLRSHSLHYLFMGASEQDLGLSLFEALGYVDDQLFVFYD H E S RRVEPRTPWVSSRISSQ           MWLQLSQSLK G WDHMFTVDFWTIMENHNHSK ESHTLQVILGCEMQEDNSTEGYWKYGYDG       QDHLEFCPDTLDWRAAEPRAWPTKLEWERHKIRARQNRAYLERDCPAQLQQLLELGRGVL       DQQVPPLVKVTHHVTSSVTTLRCRALNYYPQNITMKWLKDKQPMDAKEFEPKDVLPNGDG       TYQGWITLAVPPGEEQRYTCQVEHPGLDQPLIVIWEPSPSGTLVIGVISGIAVFVVILFI       GILFIILRKRQGSRGAMGHYVLAERE (SEQ ID NO: 2; GENBANK ® Accession       No. U60319)                    
 Residues 1-22=leader sequence; α1 domain underlined; residues 63, 65, 93, and 105 indicated in bold type) 
 
 Other mutations include nucleotide 277 of SEQ ID NO: 1, e.g., 277C which leads to expression of mutant HFE gene product G93R and one at nucleotide 193 of SEQ ID NO: 1, e.g., 193T, which leads to expression of mutant HFE gene product S65C. 
 
         [0006]     Any biological sample containing an HFE nucleic acid or gene product is suitable for the diagnostic methods described herein. For example, the biological sample to be analyzed is whole blood, cord blood, serum, saliva, buccal tissue, plasma, effusions, ascites, urine, stool, semen, liver tissue, kidney tissue, cervical tissue, cells in amniotic fluid, cerebrospinal fluid, hair or tears. Prenatal testing can be done using methods used in the art, e.g., amniocentesis or chorionic villa sampling. Preferably, the biological sample is one that can be non-invasively obtained, e.g., cells in saliva or from hair follicles.  
         [0007]     The assay is also used to screen individuals prior to donating blood to blood banks and to test organ tissue, e.g., a donor liver, prior to transplantation into a recipient patient. Both donors and recipients are screened.  
         [0008]     In some cases, a nucleic acid is amplified prior to detecting a mutation. The nucleic acid is amplified using a first oligonucleotide primer which is 5′ to exon 2 and a second oligonucleotide primer is 3′ to exon 2. To detect mutation at nucleotide 314 of SEQ ID NO: 1, a first oligonucleotide primer which is 5′ to nucleotide 314 and a second oligonucleotide primer which is 3′ to nucleotide 314 is used in a standard amplification procedure such as polymerase chain reaction (PCR). To amplify a nucleic acid containing nucleotide 277 of SEQ ID NO: 1, a first oligonucleotide primer which is 5′ to nucleotide 277 and a second oligonucleotide primer which is 3′ to nucleotide 277 is used. Similarly, a nucleic acid containing nucleotide 193 of SEQ ID NO:1 is amplified using primers which flank that nucleotide. For example, for nucleotide 277, the first primer has a nucleotide sequence of SEQ ID NO: 3 and said second oligonucleotide primer has a nucleotide sequence of SEQ ID NO: 4, or the first primer has a nucleotide sequence of SEQ ID NO: 15 and said second oligonucleotide primer has a nucleotide sequence of SEQ ID NO: 16. Table 3, below, shows examples of primer pairs for amplification of nucleic acids in exons and introns of the HFE gene.  
                                                                                             TABLE 3                           I. PRIMERS USED FOR AMPLIFICATION                Target                    DNA   Forward Primer   Reverse Primer                    Exon 2   CCTCCTACTACACATGGTTAAGG   GCTCTGACAACCTCAGGAAGG               (SEQ ID NO: 3)   (SEQ ID NO: 4)               Exon 3   GGTGGAAATAGGGACCTATTCC   CACTCTGCCACTAGACTATAGG           (SEQ ID NO: 5)   (SEQ ID NO: 6)               Exon 4   GTTCCAGTCTTCCTGGCAAGG   AAATGCTTCCCATGGATGCCAG           (SEQ ID NO: 7)   (SEQ ID NO: 8)               RT-PCR   AAAGGATCCACCATGGGCCCGCGAGCCAGG   GTGAGTCTGCAGGCTGCGTG           (SEQ ID NO: 9)   (SEQ ID NO: 10)               Intron 4   GTTCCAGTCTTCCTGGCAAGG   AAATGCTTCCCATGGATGCCAG           (SEQ ID NO: 11)   (SEQ ID NO: 12)               Intron 5   GTTCCAGTCTTCCTGGCAAGG   AAATGCTTCCCATGGATGCCAG           (SEQ ID NO: 13)   (SEQ ID NO: 14)                            II. PRIMERS USED FOR AMPLIFICATION                Exon 2   GTGTGGAGCCTCAACATCCTG   ACAAGACCTCAGACTTCCAGC               (SEQ ID NO: 15)   (SEQ ID NO: 16)               Exon 3   GGTGGAAATAGGGACCTATTCC   CACTCTGCCACTAGAGTATAGG           (SEQ ID NO: 17)   (SEQ ID NO: 18)               Exon 4   GTTCCAGTCTTCCTGGCAAGG   TTACCTCCTCAGGCACTCCTC           (SEQ ID NO: 19)   (SEQ ID NO: 20)               RT-PCR   AAAGGATCCACCATGGGCCCGCGAGCCAGG   GTGAGTCTGCAGGCTGCGTG           (SEQ ID NO: 21)   (SEQ ID NO: 22)               Intron 4   TGCCTGAGGAGGTAATTATGG   AAATGCTTCCCATGGATGCCAG           (SEQ ID NO: 23)   (SEQ ID NO: 24)               Intron 5   TGCCTGAGGAGGTAATTATGG   AAATGCTTCCCATGGATGCCAG           (SEQ ID NO: 25)   (SEQ ID NO: 26)                  
 
         [0009]     Mutations in introns of the HFE gene have now been associated with iron disorders and/or hemochromatosis. By “exon” is meant a segment of a gene the sequence of which is represented in a mature RNA product, and by “intron” is meant a segment of a gene the sequence of which is not represented in a mature RNA product. An intron is a part of a primary nuclear transcript which is subsequently spliced out to produce a mature RNA product, i.e., a mRNA, which is then transported to the cytoplasm. A method of diagnosing an iron disorder or a genetic susceptibility to developing the disorder is carried out by determining the presence or absence of a mutation in an intron of HFE genomic DNA in a biological sample. The presence of the mutation is indicative of the disorder or a genetic susceptibility to developing the disorder. The presence of a mutation in an intron is a marker for an exon mutation, e.g., a mutation in intron 4, e.g., at nucleotide 6884 of SEQ ID NO:27 is associated with the S65C mutation in exon 2. A mutation in intron 5, e.g., at nucleotide 7055 of SEQ ID NO:27 is associated with hemochromatosis. In some cases, intron mutations may adversely affect proper splicing of exons or may alter regulatory signals. Preferably, the intron 4 mutation is 6884C and the intron 5 mutation is 7055G. To amplify nucleic acid molecule containing nucleotide 6884 or 7055, primers which flank that nucleotide, e.g., those described in Table 3, are used according to standard methods. Nucleic acid-based diagnostic methods may or may not include a step of amplification to increase the number of copies of the nucleic acid to be analyzed. To detect a mutation in intron 4, a patient-derived nucleic acid may be amplified using a first oligonucleotide primer which is 5′ to intron 4 and a second oligonucleotide primer which is 3′ to intron 4, and to detect a mutation in intron 5, the nucleic acid may be amplified using a first oligonucleotide primer which is 5′ to intron 5 and a second oligonucleotide primer which is 3′ to intron 5 (see, e.g., Table 3).  
         [0010]     In addition to nucleic acid-based diagnostic methods, the invention includes a method of diagnosing an iron overload disorder or a genetic susceptibility thereto by determining the presence of a mutation in a HFE gene product in a biological sample. For example, the mutation results in a decrease in intramolecular salt bridge formation in the mutant HFE gene product compared to salt bridge formation in a wild type HFE gene product. The mutation which affects salt bridge formation is at or proximal to residue 63 of SEQ ID NO:2, but is not amino acid is substitution H63D. Preferably, the mutation is between residues 23-113, inclusive of SEQ ID NO:2 (Table 2), more preferably, it is between residues 90-100, inclusive, of SEQ ID NO:2, more preferably, it is between residues 58-68, inclusive, of SEQ ID NO:2, and most preferably, the mutation is amino acid substitution S65C. Alternatively, the mutation which affects salt bridge formation is a mutation, e.g., an amino acid substitution at residue 95 or proximal to residue 95 of SEQ ID NO:2. Preferably, the mutation is G93R. Such an HFE mutation is detected by immunoassay or any other ligand binding assay such as binding of the HFE gene product to a transferrin receptor. Mutations are also detected by amino acid sequencing, analysis of the structural conformation of the protein, or by altered binding to a carbohydrate or peptide mimetope.  
         [0011]     A mutation indicative of an iron disorder or a genetic susceptibility to developing such a disorder is located in the α1 helix (e.g., which spans residues 80-108, inclusive, of SEQ ID NO:2) of an HFE gene product. The mutation may be an addition, deletion, or substitution of an amino acid in the wild type sequence. For example, the mutant HFE gene product contains the amino acid substitution I105T or G93R or in the loop of the β sheet of the HFE molecule, e.g., mutation S65C  
         [0012]     Isolated nucleic acids encoding a mutated HFE gene products (and nucleic acids with nucleotide sequences complementary to such coding sequences) are also within the invention. Also included are nucleic acids which are at least 12 but less than 100 nucleotides in length. An isolated nucleic acid molecule is a nucleic acid molecule that is separated from the 5′ and 3′ sequences with which it is immediately contiguous in the naturally occurring genome of an organism. “Isolated” nucleic acid molecules include nucleic acid molecules which are not naturally occurring. For example, an isolated nucleic acid is one that has been amplified in vitro, e.g, by PCR; recombinantly produced; purified, e.g., by enzyme cleavage and gel separation; or chemically synthesized. For example, the restriction enzyme, Bst4C I (Sib Enzyme Limited, Novosibirsk, Russia), can be used to detect the G93R mutation (point mutation 277C); this enzyme cuts the mutated HFE nucleic acid but not the wild type HFE nucleic acid. Such nucleic acids are used as markers or probes for disease states. For example, a marker is a nucleic acid molecule containing a nucleotide polymorphism, e.g., a point mutation, associated with an iron disorder disease state flanked by wild type HFE sequences. The invention also encompasses nucleic acid molecules that hybridize, preferably under stringent conditions, to a nucleic acid molecule encoding a mutated HFE gene product (or a complementary strand of such a molecule). Preferably the hybridizing nucleic acid molecule is 400 nucleotides, more preferably 200 nucleotides, more preferably 100, more preferably 50, more preferably 25 nucleotides, more preferably 20 nucleotides, and most preferably 10-15 nucleotides, in length. For example, the nucleotide probe to detect a mutation is 13-15 nucleotides long. The nucleic acids are also used to produce recombinant peptides for generating antibodies specific for mutated HFE gene products. In preferred embodiments, an isolated nucleic acid molecule encodes an HFE polypeptide containing amino acid substitution I105T, G93R, or S65C, as well as nucleic acids the sequence of which are complementary to such nucleic acid which encode a mutant or wild type HFE gene product.  
         [0013]     Also within the invention are substantially pure mutant HFE gene products, e.g., an HFE polypeptide containing amino acid substitution I105T, G93R, or S65C. Substantially pure or isolated HFE polypeptides include those that correspond to various functional domains of HFE or fragments thereof, e.g., a fragment of HFE that contains the α1 domain.  
         [0014]     Wild type HFE binds to the transferrin receptor and regulates the affinity of transferrin receptor binding to transferrin. For example, a C282Y mutation in the HFE gene product reduces binding to the transferrin receptor, thus allowing the transferrin receptor to bind to transferrin (which leads to increased iron absorption).  
         [0015]     The polypeptides of the invention encompass amino acid sequences that are substantially identical to the amino acid sequence shown in Table 2 (SEQ ID NO:2). Polypeptides of the invention are recombinantly produced, chemically synthesized, or purified from tissues in which they are naturally expressed according to standard biochemical methods of purification. Biologically active or functional polypeptides are those which possess one or more of the biological functions or activities of wild type HFE, e.g., binding to the transferrin receptor or regulation of binding of transferrin to the transferrin receptor. A functional polypeptide is also considered within the scope of the invention if it serves as an antigen for production of antibodies that specifically bind to an HFE epitope. In many cases, functional polypeptides retain one or more domains present in the naturally-occurring form of HFE.  
         [0016]     The functional polypeptides may contain a primary amino acid sequence that has been altered from those disclosed herein. Preferably, the cysteine residues in exons 3 and 4 remain unchanged. Preferably the modifications consist of conservative amino acid substitutions. The terms “gene product”, “protein”, and “polypeptide” are used herein to describe any chain of amino acids, regardless of length or post-translational modification (for example, glycosylation or phosphorylation). Thus, the term “HFE polypeptide or gene product” includes full-length, naturally occurring HFE protein, as well a recombinantly or synthetically produced polypeptide that correspond to a full-length naturally occurring HFE or to a particular domain or portion of it.  
         [0017]     The term “purified” as used herein refers to a nucleic acid or peptide that is substantially free of cellular material, viral material, or culture medium when produced by recombinant DNA techniques, or chemical precursors or other chemicals when chemically synthesized. Polypeptides are said to be “substantially pure” when they are within preparations that are at least 60% by weight (dry weight) the compound of interest. Preferably, the preparation is at least 75%, more preferably at least 90%, and most preferably at least 99%, by weight the compound of interest. Purity can be measured by any appropriate standard method, for example, by column chromatography, polyacrylamide gel electrophoresis, or HPLC analysis.  
         [0018]     Diagnostic kits for identifying individuals suffering from or at risk of developing an iron disorder are also within the invention. A kit for detecting a nucleotide polymorphism associated with an iron disorder or a genetic susceptibility thereto contains an isolated nucleic acid which encodes at least a portion of the wild type or mutated HFE gene product, e.g., a portion which spans a mutation diagnostic for an iron disorder or hemochromatosis (or a nucleic acid the sequence of which is complementary to such a coding sequence). A kit for the detection of the presence of a mutation in exon 2 of an HFE nucleic acid contains a first oligonucleotide primer which is 5′ to exon 2 and a is second oligonucleotide primer is 3′ to exon 2, and a kit for an antibody-based diagnostic assay includes an antibody which preferentially binds to an epitope of a mutant HFE gene product, e.g., an HFE polypeptide containing amino acid substitution I105T, G93R, or S65C, compared to its binding to the wild type HFE polypeptide. An increase in binding of the mutant HFE-specific antibody to a patient-derived sample (compared to the level of binding detected in a wild type sample or sample derived from a known normal control individual) indicates the presence of a mutation which is diagnostic of an iron disorder, i.e., that the patient from which the sample was taken has an iron disorder or is at risk of developing one. The kit may also contain an antibody which binds to an epitope of wild type HFE which contains residue 105, 93, or 65. In the latter case, reduced binding of the antibody to a patient-derived HFE gene product (compared to the binding to a wild type HFE gene product or a gene product derived from a normal control individual) indicates the presence of a mutation which is diagnostic of an iron disorder, i.e., that the patient from which the sample was taken has an iron disorder or is at risk of developing one.  
         [0019]     Individual mutations and combinations of mutations in the HFE gene are associated with varying severity of iron disorders. For example, the C282Y mutation in exon 4 is typically associated with clinical hemochromatosis, whereas other HFE mutations or combinations of mutations in HFE nucleic acids are associated with disorders of varying prognosis. In some cases, hemochromatosis patients have been identified which do not have a C282Y mutation. The I105T and G93R mutations are each alone associated with an increased risk of iron overload (compared to, e.g., the H63D mutation alone), and the presence of both the I105T and H63D mutation is associated with hemochromatosis. Accordingly, the invention includes a method of determining the prognosis for hemochromatosis in a mammal suffering from or at risk of developing said hemochromatosis by (a) detecting the presence or absence of a first mutation in exon 4 in each allele of an HFE nucleic acid, e.g., patient-derived chromosomal DNA, and (b) detecting the presence of a second mutation in exon 2 in each allele of the nucleic acid. The presence of the first mutation in both chromosomes, i.e. an exon 4 homozygote such as a C282Y homozygote, indicates a more negative prognosis compared to the presence of the second mutation in one or both chromosomes, i.e., an exon 2 heterozygote or homozygote. An exon 4 mutation homozygote is also associated with a more negative prognosis compared to the presence of a first mutation (exon 4) in one allele and the presence of the second mutation (exon 2) in one allele, i.e., a compound heterozygote.  
         [0020]     Other features and advantages of the invention will be apparent from the following detailed description, and from the claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a diagram of the family of proband 1 (HFE genotype H63D/I105T). □=male, ●=female, ø=deceased, ▪=hemochromatosis phenotype. Proband 1 is indicated by an arrow. Phenotype and genotype data: age in year saturation; % Ftn=serum ferritin concentration. I105 separate chromosomes. The sister of the proband (II, 203) has hyperferritinemia.  
         [0022]      FIG. 2  is a diagram of the family of proband 2 (HFE genotype C282Y/G93R). Symbols and abbreviations are the same as those described for  FIG. 1 . Proband 2 is indicated with an arrow. G93R, C282Y, and wt alleles are known to exist only on separate chromosomes. The father and sister of the proband are being treated for hemochromatosis.  
         [0023]      FIG. 3  is a diagram of the family of proband 3 (HFE genotype C282Y/S65C). Symbols and abbreviations are the same as those described for  FIG. 1 . Proband 3 is indicated with an arrow. S65C, C282Y, and wt alleles are know to exist only on separate chromosomes. Proband 3 also has porphyria cutanea tarda, and her brother (II, 203) has ankylosing spondylitis. 
     
    
     DETAILED DESCRIPTION  
       [0024]     A proband is the first individual in a family identified to be affected by hemochromatosis. Forward and reverse sequencing of HFE exons 2, 3, 4, and 5, and of portions of HFE introns 2, 4, and 5 was carried out on biological samples taken from twenty hemochromatosis probands who lacked C282Y homozygosity, C282Y/H63D compound heterozygosity, or H63D homozygosity. Four probands had novel HFE coding region mutations. Probands 1 and 2 were heterozygous for previously undescribed mutations: exon 2, nt 314T→C (314C; I105T), and exon 2, nt 277G→C (277C; G93R), respectively; these probands were also heterozygous for H63D and C282Y, respectively. Probands 3 and 4 were heterozygous for an HFE mutation in exon 2, nt 193A→T (193T; S65C). Twelve other probands did not have an exon 2 HFE exon mutation; four were heterozygous for H63D. In probands 1, 2, 3, and 4, the amino acid substitutions I105T, G93R, and S65C (respectively) occurred on separate chromosomes from those with the C282Y or H63D mutations. In 176 normal control subjects, two were heterozygous for S65C; I105T and G93R were not detected in controls. Nine probands were heterozygous and two probands were homozygous for a base-pair change at intron 2, nt 4919T/C (SEQ ID NO:27). Heterozygosity for a base-pair change in intron 4 (nt 6884T→C) was detected only in probands 3 and 4, both of whom also had S65C and HLA-A32. The intron 2 mutation is not diagnostic of an iron disorder and appears randomly in the population. One proband was heterozygous for a base-pair change at intron 5 (nt 7055A→G).  
         [0025]     The data described herein indicate that, in addition to the C282Y and H63D HFE mutations, the HFE exon and intron 5 mutations described herein are diagnostic (and prognostic) of iron disorders.  
         [0000]     Pathology of Iron Overload  
         [0026]     Iron plays an essential role in normal growth and development, but in elevated concentrations, iron is a toxic inorganic molecule and is the leading cause of death in children by poisoning. It has been implicated in the pathophysiology of a number of common diseases, e.g., hepatitis, cancer, heart disease, reperfusion injury, rheumatoid arthritis, diabetes, AIDS, and psychological abnormalities (e.g. depression).  
         [0027]     The incidence of cancer (especially liver cancer) rises dramatically in the course of hemochromatosis. Iron, acting alone or in synergy with other environmental agents, catalyzes free radical formation. These free radicals which mediate tissue damage also cause DNA double strand breaks and oncogene activation. Iron may also play a role in the pathogenesis of rheumatic diseases and in predisposition to heart disease. High levels of iron can also cause diabetes with 2% of diabetics being hemochromatosis patients. High levels of iron may also affect the disease progression of many viral diseases. Individuals infected with such viruses as hepatitis (e.g., hepatitis B or C) or HIV should be tested for HFE mutations because of the impact increased iron stores have on the treatment and prognosis of such diseases.  
         [0028]     Excessive iron stores and iron deposition is also a major contributing factor in the pathology and treatment of non-valvular heart disease. These conditions include dilated cardiomyopathy cased by deposition of iron in myocardial fibers; myocardial injury the product of anthracycline cardiomyopathy and re-perfusion injury. Increased iron stores may also be a contributing factor in myocardial infarction due to atherosclerosis. Some evidence suggests a significant increase in the incidence of reported heart disease in probands (cardiac symptoms-32%, insulin-dependent diabetes-18%, cardiac arrhythmia-17%, clinically significant coronary artery atherosclerosis-9%, and congestive heart failure-7%. Cardiac complications have been detected in 30% of patients. These include EKG abnormalities, congestive heart failure and cardiac arrhythmias. An increased frequency of HFE mutations in individuals with porphyria cutanea tarda indicates that HFE mutations may predipose an individual to developing this syndrome.  
         [0029]     The effect of iron overload is irreparable damage to vital organs and a multiplicity of associated pathologies described above. The multiplicity of clinical symptoms (and associated pathologies) often causes misdiagnosis of hemochromatosis or failure to diagnose hemochromatosis.  
         [0030]     Untreated hemochromatosis is characterized by iron overload of parenchymal cells, which is toxic and the probable cause of various complications including cirrhosis, and liver cancer, arthropathy, hypogonadotropic hypogonadism, marrow aplasia, skin disorders, diabetes mellitus, and cardiomyopathy. There are 1.5 to 2 million active cases in the U.S. of which 40% have progressive liver disease because they have not been properly diagnosed or treated.  
         [0031]     In untreated hemochromatosis, iron is universally deposited in the hepatocytes of the liver. The iron is found primarily in the cytoplasm of hepatocytes, and by electron microscopy in lysosomal vacuoles, and in more severe cases iron has also been reported deposited in mitochondria. Other liver toxins such as alcohol, and hepatitis exacerbate the damage caused by the iron deposition. Patients with hemochromatosis are advised not to drink, because of increased liver damage, or to smoke, as iron deposition can also occur in the lungs.  
         [0032]     Individuals which are homozygous (and to a lesser extent heterozygous) for an HFE mutation are at risk for developing increased levels of blood lead. Thus, it is important to identify heterozygous as well as homozygous patients.  
         [0033]     Identification and detection of mutations in the HFE gene are critical to understanding the general mechanisms of iron disorders and diagnosing iron-related pathologies.  
         [0000]     Nucleic Acid-Based Assays for HFE Mutations  
         [0034]     A biological sample containing RNA or DNA is obtained from an individual and the nucleic acid extracted. Optionally, the nucleic acid is amplified according to standard procedures such as PCR. A nucleic acid polymorphism, e.g, a single base pair polymorphism, is detected using methods well known in the art of molecular biology. For example, a mutation is detected using a standard sequencing assay, nucleic acid hybridization, e.g, using standard Southern, Northern, or dot blot hybridization assay systems and an HFE-specific oligonucleotide probe, restriction enzyme fragment polymorphism analysis, oligonucleotide ligation assay (OLA; Nikerson et al., 1990, Nucl. Acids Res. 87:8923-8927), primer extension analysis (Nikiforov et al., 1994, Nucl. Acids Res. 22:4167-4175), single strand conformation polymorphism (SSCP) analysis, allele-specific PCR (Rust et al., 1993, Nucl. Acids Res. 6:3623-3629), denaturing gradient gel electrophoresis (DGGE), fluorescent probe melting curve analysis (Bernard et al., 1998, Am. J. Pathol. 153:1055-61), RNA mismatch cleavage assay, capillary hybridization, or TaqMan™ assay (PE Applied Biosystems, Foster City, Calif.). Nucleic acid hybridization assays are also carried out using a bioelectronic microchip technology known in the art, e.g., that described in Sosnowski et al., 1997, Proc. Natl. Acad. Sci. U.S.A. 94:1119-1123; Cheng et al. 1998, Nature Biotechnology 16:541-546; or Edman et al., 1997, Nucl. Acids Res. 25:4907-4914.  
         [0000]     Detection of Mutations Using Antibodies and Other HFE Ligands  
         [0035]     Anti-HFE antibodies are know in the art, e.g., those described by Feder et al., 1997, J. Biol. Chem. 272:14025-14028, or are obtained using standard techniques. Such antibodies can be polyclonal or monoclonal. Polyclonal antibodies can be obtained, for example, by the methods described in Ghose et al., Methods in Enzymology, Vol. 93, 326-327, 1983. An HFE polypeptide, or an antigenic fragment thereof, is used as an immunogen to stimulate the production of HFE-reactive polyclonal antibodies in the antisera of animals such as rabbits, goats, sheep, rodents and the like. HFE antibodies specific for mutated HFE gene products are raised by immunizing animals with a polypeptide spanning the mutation, e.g, a polypeptide which contains the mutations described herein. For example, the entire α1 domain of a mutant HFE gene product is used as an immunogen. Monoclonal antibodies are obtained by the process described by Milstein and Kohler in Nature, 256:495-97, 1975, or as modified by Gerhard, Monoclonal Antibodies, Plenum Press, 1980, pages 370-371. Hybridomas are screened to identify those producing antibodies that are highly specific for an HFE polypeptide containing a mutation characteristic of an iron metabolism abnormality or clinical hemochromatosis. Preferably, the antibody has an affinity of at least about 10 5  liters/mole, preferably at least 106 liters/mole, more preferably at least 108 liters/mole, and most preferably, an affinity of at least about 10 9  liters/mole.  
         [0036]     Antibodies specific for the wild type HFE can also be used to diagnose hemochromatosis or iron metabolism abnormalities. Such antibodies are also useful research tools to identify novel mutations indicative of iron disorders or hemochromatosis. A reduction in binding to a wild type HFE-specific antibody indicates the presence of a mutation. Antibody binding is detected using known methods. For example, an ELISA assay involves coating a substrate, e.g., a plastic dish, with an antigen, e.g., a patient-derived biological sample containing an HFE gene product. An antibody preparation is then added to the well. Antibodies specific for a mutant HFE gene product bind or fail to bind to a patient-derived sample in the well. Non-binding material is washed away and a marker enzyme e.g., horse radish peroxidase or alkaline phosphatase, coupled to a second antibody directed against the antigen-specific primary antibody is added in excess and the nonadherent material is washed away. An enzyme substrate is added to the well and the enzyme catalyzed conversion is monitored as is indicative of presence of the mutation. Antibodies are also labelled with various sizes of colloidal gold particles or latex particles for detection of binding.  
         [0037]     The invention employs not only intact monoclonal or polyclonal antibodies, but also an immunologically-active antibody fragment, for example, a Fab or (Fab) 2  fragment; an antibody heavy chain, an antibody light chain; a genetically engineered single-chain Fv molecule (Ladner et al., U.S. Pat. No. 4,946,778).  
       EXAMPLE 1  
     Selection and Characterization of Subjects  
       [0038]     All individuals studied were Caucasians, 18 years of age or older, and from central Alabama. Twenty probands were identified that were either heterozygous for C282Y or H63D, or lacked these mutations. Hemochromatosis is typically diagnosed by detecting elevated saturation of transferrin, with elevated serum ferritin levels, combined with liver biopsy. Each proband patient described below was previously diagnosed to have hemochromatosis by the working diagnostic criterion for hemochromatosis of the American College of Pathologists (elevated fasting transferrin saturation of greater than 60% saturation for males and greater than 50% saturation for females) on at least two occasions in the absence of other known causes. Probands were interviewed regarding their general medical history, diet (including estimated iron content and ethanol consumption), medicinal iron use, receipt of blood transfusion, prior significant hemorrhage, blood donation for transfusion and/or therapeutic phlebotomy, and pregnancy and lactation. Each proband was also evaluated for viral hepatitis B and C and other hepatic disorders, excess ethanol intake, and hereditary, and acquired anemia. Iron overload was defined as evidence of systemic iron overload demonstrated by otherwise unexplained elevated serum is ferritin concentration (≧300 ng/mL in men, ≧200 ng/mL in women), increased hepatic iron content determined using hepatic biopsy specimens, or iron &gt;4 g mobilized by phlebotomy. Complications of iron overload were evaluated and treated, and therapeutic phlebotomy was performed using standard methods. HFE mutation analysis for C282Y and H63D and human leukocyte antigen (HLA) immunophenotyping or molecular typing were performed using known methods. In some family members, HLA haplotyping had been performed previously for other disease associations, or their HLA type could be deduced from analysis of their kinship and HFE genotyping results. Measurement of serum iron and other clinical laboratory parameters and analysis of hepatic biopsy specimens were performed using routine methods. Control subjects (n=176) who were in apparently good health and were unrelated to the hemochromatosis probands were recruited from the general population. Iron parameters were measured and HLA typing was performed in two control subjects after HFE genotyping revealed that they had the S65C mutation.  
       EXAMPLE 2  
     HFE Gene Analysis  
       [0039]     PCR amplification was used to detect mutations. Genomic DNA was prepared from peripheral blood buffy coat or saliva using the QIAmpBlood Kit (QIAGEN, Valencia, Calif.) or FTA Paper and FTA purification reagent (Fitzco Inc., Maple Plain, Minn.), respectively. Fragments were amplified from genomic DNA using eLONGase (Life Technologies, Gaithersburg, Md.) or HotStarTaq DNA polymerase (QIAGEN, Valencia, Calif.). Primers used to amplify each exon are shown in Table 3.  
                                                 TABLE 4                       Human HFE genomic DNA                                1   ggatccttta   accgaggaga   ttattatagc   cggagctctg   aagcagcaat   ctcagttctt                   61   gtgatagtga   gcaaagaact   acaaactaac   accaaaatgc   aagcttaaag   caaagtttat               121   tgaagcacaa   taatacactc   tgagggacag   cgggcttatt   tctgcgaagt   gaactcagca               181   cttctttaca   gagctcaagg   tgcttttatg   gggtttgtgg   ggaggagttg   aggtttgggc               241   tgtatctgag   tgacaggatg   atgttatttg   attgaagttt   atagctatac   aatctaaaat               301   taaactgtgc   atggtcttac   ctataatttg   ttaagaaaag   cctcccaggg   atgggggggc               361   aaaactgtat   gtaaattcta   ttataatgat   ggcatgatga   acttggggtg   aacttgaaga               421   caggcttttg   tgttgttggg   catgtgccac   cttagggaat   ttccacctgt   accctccttt               481   ctctttctcc   aggatatttt   ggccacagac   tttatcataa   actccatccc   ttagggtggc               541   attagggtag   tcttgggcct   gaatttaggt   gggccagtgg   ctgtcttagt   gacagccttt               601   ccgctctctt   ctgtcatccc   ctcccaactg   ctaatgtcta   actacctaac   aattacccat               661   taaatcagtg   tgtctggggt   taggagcagg   cctcaatatg   tttaatcatt   ctccagataa               721   tcccaatact   gtaaagtttg   tgaaacactt   gtcagataat   tcaattatga   aggctgtgga               781   acgtgtttca   gtaggatcta   attggttaat   gttatgactt   aattaatttg   aatcaaaaaa               841   caaaatgaaa   aagctttata   tttctaagtc   aaataagaca   taagttggtc   taaggttgag               901   ataaaatttt   taaatgtatg   attgaatttt   gaaaatcata   aatatttaaa   tatctaaagt               961   tcagatcaga   acattgcgaa   gctactttcc   ccaatcaaca   acaccccttc   aggatttaaa               1021   aaccaagggg   gacactggat   cacctagtgt   ttcacaagca   ggtaccttct   gctgtaggag               1081   agagagaact   aaagttctga   aagacctgtt   gcttttcacc   aggaagtttt   actgggcatc               1141   tcctgagcct   aggcaatagc   tgtagggtga   cttctggagc   catccccgtt   tccccgcccc               1201   ccaaaagaag   cggagattta   acggggacgt   gcggccagag   ctggggaaat   gggcccgcga               1261   gccaggccgg   cgcttctcct   cctgatgctt   ttgcagaccg   cggtcctgca   ggggcgcttg               1321   ctgcgtgagt   ccgagggctg   cgggcgaact   aggggcgcgg   cgggggtgga   aaaatcgaaa               1381   ctagcttttt   ctttgcgctt   gggagtttgc   taactttgga   ggacctgctc   aacccaatcc               1441   gcaagcccct   ctccctactt   tctgcgtcca   gaccccgtga   gggagtgcct   accactgaac               1501   tgcagatagg   ggtccctcgc   cccaggacct   gccccctccc   ccggctgtcc   cggctctgcg               1561   gagtgacttt   tggaaccgcc   cactcccttc   ccccaactag   aatgctttta   aataaatctc               1621   gtagttcctc   acttgagccg   agctaagcct   ggggctcctt   gaacctggaa   ctcgggttta               1681   tttccaatgt   cagctgtgca   gttttttccc   cagtcatctc   caaacaggaa   gttcttccct               1741   gagtgcttgc   cgagaaggct   gagcaaaccc   acagcaggat   ccgcacgggg   tttccacctc               1801   agaacgaatg   cgttgggcgg   tgggggcgcg   aaagagtggc   gttggggatc   tgaattcttc               1861   accattccac   ccacttttgg   tgagacctgg   ggtggaggtc   tctagggtgg   gaggctcctg               1921   agagaggcct   acctcgggcc   tttccccact   cttggcaatt   gttcttttgc   ctggaaaatt               1981   aagtatatgt   tagttttgaa   cgtttgaact   gaacaattct   cttttcggct   aggctttatt               2041   gatttgcaat   gtgctgtgta   attaagaggc   ctctctacaa   agtactgata   atgaacatgc               2101   aagcaatgca   ctcacttcta   agttacattc   atatctgatc   ttatttgatt   ttcactaggc               2161   atagggaggt   aggagctaat   aatacgttta   ttttactaga   agttaactgg   aattcagatt               2221   atataactct   tttcaggtta   caaagaacat   aaataatctg   gttttctgat   gttatttcaa               2281   gtactacagc   tgcttctaat   cttagttgac   agtgattttg   ccctgtagtg   tagcacagtg               2341   ttctgtgggt   cacacgccgg   cctcagcaca   gcactttgag   ttttggtact   acgtgtatcc               2401   acattttaca   catgacaaga   atgaggcatg   gcacggcctg   cttcctggca   aatttattca               2461   atggtacacg   gggctttggt   ggcagagctc   atgtctccac   ttcatagcta   tgattcttaa               2521   acatcacact   gcattagagg   ttgaataata   aaatttcatg   ttgagcagaa   atattcattg               2581   tttacaagtg   taaatgagtc   ccagccatgt   gttgcactgt   tcaagcccca   agggagagag               2641   cagggaaaca   agtctttacc   ctttgatatt   ttgcattcta   gtgggagaga   tgacaataag               2701   caaatgagca   gaaagatata   caacatcagg   aaatcatggg   tgttgtgaga   agcagagaag               2761   tcagggcaag   tcactctggg   gctgacactt   gagcagagac   atgaaggaaa   taagaatgat               2821   attgactggg   agcagtattt   cccaggcaaa   ctgagtgggc   ctggcaagtt   ggattaaaaa               2881   gcgggttttc   tcagcactac   tcatgtgtgt   gtgtgtgggg   gggggggcgg   cgtgggggtg               2941   ggaaggggga   ctaccatctg   catgtaggat   gtctagcagt   atcctgtcct   ccctactcac               3001   taggtgctag   gagcactccc   ccagtcttga   caaccaaaaa   tgtctctaaa   ctttgccaca               3061   tgtcacctag   tagacaaact   cctggttaag   aagctcgggt   tgaaaaaaat   aaacaagtag               3121   tgctggggag   tagaggccaa   gaagtaggta   atgggctcag   aagaggagcc   acaaacaagg               3181   ttgtgcaggc   gcctgtaggc   tgtggtgtga   attctagcca   aggagtaaca   gtgatctgtc               3241   acaggctttt   aaaagattgc   tctggctgct   atgtggaaag   cagaatgaag   ggagcaacag               3301   taaaagcagg   gagcccagcc   aggaagctgt   tacacagtcc   aggcaagagg   tagtggagtg               3361   ggctgggtgg   gaacagaaaa   gggagtgaca   aaccattgtc   tcctgaatat   attctgaagg               3421   aagttgctga   aggattctat   gttgtgtgag   agaaagagaa   gaattggctg   ggtgtagtag               3481   ctcatgccaa   ggaggaggcc   aaggagagca   gattcctgag   ctcaggagtt   caagaccagc               3541   ctgggcaaca   cagcaaaacc   ccttctctac   aaaaaataca   aaaattagct   gggtgtggtg               3601   gcatgcacct   gtgatcctag   ctactcggga   ggctgaggtg   gagggtattg   cttgagccca               3661   ggaagttgag   gctgcagtga   gccatgactg   tgccactgta   cttcagccta   ggtgacagag               3721   caagaccctg   tctcccctga   ccccctgaaa   aagagaagag   ttaaagttga   ctttgttctt               3781   tattttaatt   ttattggcct   gagcagtggg   gtaattggca   atgccatttc   tgagatggtg               3841   aaggcagagg   aaagagcagt   ttggggtaaa   tcaaggatct   gcatttggac   atgttaagtt               3901   tgagattcca   gtcaggcttc   caagtggtga   ggccacatag   gcagttcagt   gtaagaattc               3961   aggaccaagg   cagggcacgg   tggctcactt   ctgtaatccc   agcactttgg   tggctgaggc               4021   aggtagatca   tttgaggtca   ggagtttgag   acaagcttgg   ccaacatggt   gaaaccccat               4081   gtctactaaa   aatacaaaaa   ttagcctggt   gtggtggcgc   acgcctatag   tcccaggttt               4141   tcaggaggct   taggtaggag   aatcccttga   acccaggagg   tgcaggttgc   agtgagctga               4201   gattgtgcca   ctgcactcca   gcctgggtga   tagagtgaga   ctctgtctca   aaaaaaaaaa               4261   aaaaaaaaaa   aaaaaaaaaa   aactgaagga   attattcctc   aggatttggg   tctaatttgc               4321   cctgagcacc   aactcctgag   ttcaactacc   atggctagac   acaccttaac   attttctaga               4381   atccaccagc   tttagtggag   tctgtctaat   catgagtatt   ggaataggat   ctgggggcag               4441   tgagggggtg   gcagccacgt   gtggcagaga   aaagcacaca   aggaaagagc   acccaggact               4501   gtcatatgga   agaaagacag   gactgcaact   cacccttcac   aaaatgagga   ccagacacag               4561   ctgatggtat   gagttgatgc   aggtgtgtgg   agcctcaaca   tcctgctccc   ctcctactac               4621   acatggttaa   ggcctgttgc   tctgtctcca   ggttcacact   ctctgcacta   cctcttcatg               4681   ggtgcctcag   agcaggacct   tggtctttcc   ttgtttgaag   ctttgggcta   cgtggatgac               4741   cagctgttcg   tgttctatga   tcatgagagt   cgccgtgtgg   agccccgaac   tccatgggtt               4801   tccagtagaa   tttcaagcca   gatgtggctg   cagctgagtc   agagtctgaa   agggtgggat               4861   cacatgttca   ctgttgactt   ctggactatt   atggaaaatc   acaaccacag   caagggtatg               4921   tggagagggg   gcctcacctt   cctgaggttg   tcagagcttt   tcatcttttc   atgcatcttg               4981   aaggaaacag   ctggaagtct   gaggtcttgt   gggagcaggg   aagagggaag   gaatttgctt               5041   cctgagatca   tttggtcctt   ggggatggtg   gaaataggga   cctattcctt   tggttgcagt               5101   taacaaggct   ggggattttt   ccagagtccc   acaccctgca   ggtcatcctg   ggctgtgaaa               5161   tgcaagaaga   caacagtacc   gagggctact   ggaagtacgg   gtatgatggg   caggaccacc               5221   ttgaattctg   ccctgacaca   ctggattgga   gagcagcaga   acccagggcc   tggcccacca               5281   agctggagtg   ggaaaggcac   aagattcggg   ccaggcagaa   cagggcctac   ctggagaggg               5341   actgccctgc   acagctgcag   cagttgctgg   agctggggag   aggtgttttg   gaccaacaag               5401   gtatggtgga   aacacacttc   tgcccctata   ctctagtggc   agagtggagg   aggttgcagg               5461   gcacggaatc   cctggttgga   gtttcagagg   tggctgaggc   tgtgtgcctc   tccaaattct               5521   gggaagggac   tttctcaatc   ctagagtctc   taccttataa   ttgagatgta   tgagacagcc               5581   acaagtcatg   ggtttaattt   cttttctcca   tgcatatggc   tcaaagggaa   gtgtctatgg               5641   cccttgcttt   ttatttaacc   aataatcttt   tgtatattta   tacctgttaa   aaattcagaa               5701   atgtcaaggc   cgggcacggt   ggctcacccc   tgtaatccca   gcactttggg   aggccgaggc               5761   gggtggtcac   aaggtcagga   gtttgagacc   agcctgacca   acatggtgaa   acccgtctct               5821   aaaaaaatac   aaaaattagc   tggtcacagt   catgcgcacc   tgtagtccca   gctaattgga               5881   aggctgaggc   aggagcatcg   cttgaacctg   ggaagcggaa   gttgcactga   gccaagatcg               5941   cgccactgca   ctccagccta   ggcagcagag   tgagactcca   tcttaaaaaa   aaaaaaaaaa               6001   aaaaagagaa   ttcagagatc   tcagctatca   tatgaatacc   aggacaaaat   atcaagtgag               6061   gccacttatc   agagtagaag   aatcctttag   gttaaaagtt   tctttcatag   aacatagcaa               6121   taatcactga   agctacctat   cttacaagtc   cgcttcttat   aacaatgcct   cctaggttga               6181   cccaggtgaa   actgaccatc   tgtattcaat   cattttcaat   gcacataaag   ggcaatttta               6241   tctatcagaa   caaagaacat   gggtaacaga   tatgtatatt   tacatgtgag   gagaacaagc               6301   tgatctgact   gctctccaag   tgacactgtg   ttagagtcca   atcttaggac   acaaaatggt               6361   gtctctcctg   tagcttgttt   ttttctgaaa   agggtatttc   cttcctccaa   cctatagaag               6421   gaagtgaaag   ttccagtctt   cctggcaagg   gtaaacagat   cccctctcct   catccttcct               6481   ctttcctgtc   aagtgcctcc   tttggtgaag   gtgacacatc   atgtgacctc   ttcagtgacc               6541   actctacggt   gtcgggcctt   gaactactac   ccccagaaca   tcaccatgaa   gtggctgaag               6601   gataagcagc   caatggatgc   caaggagttc   gaacctaaag   acgtattgcc   caatggggat               6661   gggacctacc   agggctggat   aaccttggct   gtaccccctg   gggaagagca   gagatatacg               6721   tgccaggtgg   agcacccagg   cctggatcag   cccctcattg   tgatctgggg   tatgtgactg               6781   atgagagcca   ggagctgaga   aaatctattg   ggggttgaga   ggagtgcctg   aggaggtaat               6841   tatggcagtg   agatgaggat   ctgctctttg   ttaggggatg   ggctgagggt   ggcaatcaaa               6901   ggctttaact   tgctttttct   gttttagagc   cctcaccgtc   tggcacccta   gtcattggag               6961   tcatcagtgg   aattgctgtt   tttgtcgtca   tcttgttcat   tggaattttg   ttcataatat               7021   taaggaagag   gcagggttca   agtgagtagg   aacaaggggg   aagtctctta   gtacctctgc               7081   cccagggcac   agtgggaaga   ggggcagagg   ggatctggca   tccatgggaa   gcatttttct               7141   catttatatt   ctttggggac   accagcagct   ccctgggaga   cagaaaataa   tggttctccc               7201   cagaatgaaa   gtctctaatt   caacaaacat   cttcagagca   cctactattt   tgcaagagct               7261   gtttaaggta   gtacaggggc   tttgaggttg   agaagtcact   gtggctattc   tcagaaccca               7321   aatctggtag   ggaatgaaat   tgatagcaag   taaatgtagt   taaagaagac   cccatgaggt               7381   cctaaagcag   gcaggaagca   aatgcttagg   gtgtcaaagg   aaagaatgat   cacattcagc               7441   tggggatcaa   gatagccttc   tggatcttga   aggagaagct   ggattccatt   aggtgaggtt               7501   gaagatgatg   ggaggtctac   acagacggag   caaccatgcc   aagtaggaga   gtataaggca               7561   tactgggaga   ttagaaataa   ttactgtacc   ttaaccctga   gtttgcttag   ctatcactca               7621   ccaattatgc   atttctaccc   cctgaacatc   tgtggtgtag   ggaaaagaga   atcagaaaga               7681   agccagctca   tacagagtcc   aagggtcttt   tgggatattg   ggttatgatc   actggggtgt               7741   cattgaagga   tcctaagaaa   ggaggaccac   gatctccctt   atatggtgaa   tgtgttgtta               7801   agaagttaga   tgagaggtga   ggagaccagt   tagaaagcca   ataagcattt   ccagatgaga               7861   gataatggtt   cttgaaatcc   aatagtgccc   aggtctaaat   tgagatgggt   gaatgaggaa               7921   aataaggaag   agagaagagg   caagatggtg   cctaggtttg   tgatgcctct   ttcctgggtc               7981   tcttgtctcc   acaggaggag   ccatggggca   ctacgtctta   gctgaacgtg   agtgacacgc               8041   agcctgcaga   ctcactgtgg   gaaggagaca   aaactagaga   ctcaaagagg   gagtgcattt               8101   atgagctctt   catgtttcag   gagagagttg   aacctaaaca   tagaaattgc   ctgacgaact               8161   ccttgatttt   agccttctct   gttcatttcc   tcaaaaagat   ttccccattt   aggtttctga               8221   gttcctgcat   gccggtgatc   cctagctgtg   acctctcccc   tggaactgtc   tctcatgaac               8281   ctcaagctgc   atctagaggc   ttccttcatt   tcctccgtca   cctcagagac   atacacctat               8341   gtcatttcat   ttcctatttt   tggaagagga   ctccttaaat   ttgggggact   tacatgattc               8401   attttaacat   ctgagaaaag   ctttgaaccc   tgggacgtgg   ctagtcataa   ccttaccaga               8461   tttttacaca   tgtatctatg   cattttctgg   acccgttcaa   cttttccttt   gaatcctctc               8521   tctgtgttac   ccagtaactc   atctgtcacc   aagccttggg   gattcttcca   tctgattgtg               8581   atgtgagttg   cacagctatg   aaggctgtac   actgcacgaa   tggaagaggc   acctgtccca               8641   gaaaaagcat   catggctatc   tgtgggtagt   atgatgggtg   tttttagcag   gtaggaggca               8701   aatatcttga   aaggggttgt   gaagaggtgt   tttttctaat   tggcatgaag   gtgtcataca               8761   gatttgcaaa   gtttaatggt   gccttcattt   gggatgctac   tctagtattc   cagacctgaa               8821   gaatcacaat   aattttctac   ctggtctctc   cttgttctga   taatgaaaat   tatgataagg               8881   atgataaaag   cacttacttc   gtgtccgact   cttctgagca   cctacttaca   tgcattactg               8941   catgcacttc   ttacaataat   tctatgagat   aggtactatt   atccccattt   cttttttaaa               9001   tgaagaaagt   gaagtaggcc   gggcacggtg   gctcacgcct   gtaatcccag   cactttggga               9061   ggccaaagcg   ggtggatcac   gaggtcagga   gatcgagacc   atcctggcta   acatggtgaa               9121   accccatctc   taataaaaat   acaaaaaatt   agctgggcgt   ggtggcagac   gcctgtagtc               9181   ccagctactc   ggaaggctga   ggcaggagaa   tggcatgaac   ccaggaggca   gagcttgcag               9241   tgagccgagt   ttgcgccact   gcactccagc   ctaggtgaca   gagtgagact   ccatctcaaa               9301   aaaataaaaa   taaaaataaa   aaaatgaaaa   aaaaaagaaa   gtgaagtata   gagtatctca               9361   tagtttgtca   gtgatagaaa   caggtttcaa   actcagtcaa   tctgaccgtt   tgatacatct               9421   cagacaccac   tacattcagt   agtttagatg   cctagaataa   atagagaagg   aaggagatgg               9481   ccttctcttc   gtctcattgt   gtttcttctg   aatgagcttg   aatcacatga   aggggaacag               9541   cagaaaacaa   ccaactgatc   ctcagctgtc   atgtttcctt   taaaagtccc   tgaaggaagg               9601   tcctggaatg   tgactccctt   gctcctctgt   tgctctcttt   ggcattcatt   tctttggacc               9661   ctacgcaagg   actgtaattg   gtggggacag   ctagtggccc   tgctgggctt   cacacacggt               9721   gtcctcccta   ggccagtgcc   tctggagtca   gaactctggt   ggtatttccc   tcaatgaagt               9781   ggagtaagct   ctctcatttt   gagatggtat   aatggaagcc   accaagtggc   ttagaggatg               9841   cccaggtcct   tccatggagc   cactggggtt   ccggtgcaca   ttaaaaaaaa   aatctaacca               9901   ggacattcag   gaattgctag   attctgggaa   atcagttcac   catgttcaaa   agagtctttt               9961   tttttttttt   gagactctat   tgcccaggct   ggagtgcaat   ggcatgatct   cggctcactg               10021   taacctctgc   ctcccaggtt   caagcgattc   tcctgtctca   gcctcccaag   tagctgggat               10081   tacaggcgtg   caccaccatg   cccggctaat   ttttgtattt   ttagtagaga   cagggtttca               10141   ccatgttggc   caggctggtc   tcgaactctc   ctgacctcgt   gatccgcctg   cctcggcctc               10201   ccaaagtgct   gagattacag   gtgtgagcca   ccctgcccag   ccgtcaaaag   agtcttaata               10261   tatatatcca   gatggcatgt   gttcacttta   tgttactaca   tgcacttggc   tgcataaatg               10321   tggtacaagc   attctgtctt   gaagggcagg   tgcttcagga   taccatatac   agctcagaag               10381   tttcttcttt   aggcattaaa   ttttagcaaa   gatatctcat   ctcttctttt   aaaccatttt               10441   ctttttttgt   ggttagaaaa   gttatgtaga   aaaaagtaaa   tgtgatttac   gctcattgta               10501   gaaaagctat   aaaatgaata   caattaaagc   tgttatttaa   ttagccagtg   aaaaactatt               10561   aacaacttgt   ctattacctg   ttagtattat   tgttgcatta   aaaatgcata   tactttaata               10621   aatgtacatt   gtattgtata   ctgcatgatt   ttattgaagt   tcttgttcat   cttgtgtata               10681   tacttaatcg   ctttgtcatt   ttggagacat   ttattttgct   tctaatttct   ttacattttg               10741   tcttacggaa   tattttcatt   caactgtggt   agccgaatta   atcgtgtttc   ttcactctag               10801   ggacattgtc   gtctaagttg   taagacattg   gttattttac   cagcaaacca   ttctgaaagc               10861   atatgacaaa   ttatttctct   cttaatatct   tactatactg   aaagcagact   gctataaggc               10921   ttcacttact   cttctacctc   ataaggaata   tgttacaatt   aatttattag   gtaagcattt               10981   gttttatatt   ggttttattt   cacctgggct   gagatttcaa   gaaacacccc   agtcttcaca               11041   gtaacacatt   tcactaacac   atttactaaa   catcagcaac   tgtggcctgt   taattttttt               11101   aatagaaatt   ttaagtcctc   attttctttc   ggtgtttttt   aagcttaatt   tttctggctt               11161   tattcataaa   ttcttaaggt   caactacatt   tgaaaaatca   aagacctgca   ttttaaattc               11221   ttattcacct   ctggcaaaac   cattcacaaa   ccatggtagt   aaagagaagg   gtgacacctg               11281   gtggccatag   gtaaatgtac   cacggtggtc   cggtgaccag   agatgcagcg   ctgagggttt               11341   tcctgaaggt   aaaggaataa   agaatgggtg   gaggggcgtg   cactggaaat   cacttgtaga               11401   gaaaagcccc   tgaaaatttg   agaaaacaaa   caagaaacta   cttaccagct   atttgaattg               11461   ctggaatcac   aggccattgc   tgagctgcct   gaactgggaa   cacaacagaa   ggaaaacaaa               11521   ccactctgat   aatcattgag   tcaagtacag   caggtgattg   aggactgctg   agaggtacag               11581   gccaaaattc   ttatgttgta   ttataataat   gtcatcttat   aatactgtca   gtattttata               11641   aaacattctt   cacaaactca   cacacattta   aaaacaaaac   actgtctcta   aaatccccaa               11701   atttttcata   aactcagttt   taaactaact   ttttttcaaa   ccacaatctg   atttaacaat               11761   gactatcatt   taaatatttc   tgactttcaa   attaaagatt   ttcacatgca   ggctgatatt               11821   tgtaattgtg   attctctctg   taggctttgg   gtataatgtg   ttcttttcct   tttttgcatc               11881   agcgattaac   ttctacactc   taacatgtag   aatgttacta   caatattaaa   gtattttgta               11941   tgacaatttt   atttgaaagc   ctaggatgcg   ttgacatcct   gcatgcattt   attacttgat               12001   atgcatgcat   tctggtatct   caagcattct   atttctgagt   aattgtttaa   ggtgtagaag               12061   agatagatat   ggtggatttg   gagttgatac   ttatatattt   tctatttctt   ggatggatga               12121   atttgtacat   taaaagtttt   ccatgg               (SEQ ID NO:27; GENBANK ® Accession No. Z92910)                  
 
         [0040]     Exon 1 spans nt 1028-1324, inclusive; exon 2 spans nt 4652-4915, inclusive; exon 3 spans nt 5125-5400, inclusive; exon 4 spans nt 6494-6769, inclusive; exon 5 spans nt 6928-7041, inclusive; exon 6 spans nt 7995-9050, inclusive, and exon 7 spans nt 10206-10637, inclusive. Intron 4 spans nt 6770-6927, inclusive, and intron 5 spans nt 7042-7994, inclusive.  
         [0041]     Total RNA for the RT-PCR was prepared from 1.5 mL of whole blood using the RNeasy Blood Kit (QIAGEN, Valencia, CA). Total messenger RNA encoding the HFE gene was transcribed and amplified with the primers shown above using standard methods, e.g., the Superscript ONE-STEP RT-PCR System (Life Technologies, Gaithersburg, Md.). The amplified product was directly subcloned into the pCR2.1-TOPO vector and transfected into TOP 10 bacteria (Invitrogen, Carlsbad, Calif.). Plasmid DNAs isolated from the subcloning were prepared with the UltraClean Mini Prep Kit (Mo Bio, Solana Beach, Calif.) and sequenced.  
         [0042]     DNA sequencing was performed using the ABI Prism BigDye Terminator Cycle Sequencing Ready Reaction Kit (PE Applied Biosystems, Foster City, Calif.) and analyzed on an ABI Prism 377.  
         [0043]     To detect mutations in exon 2 of the HFE gene, the genomic DNA of probands and normal control subjects were amplified and subjected to a dot blot hybridization assay. 1.0 μl of each resulting PCR product was then applied to a Magna Graph nylon membrane (MSI, Westboro, Mass.). The membranes were treated with 0.5 N NaOH/1.5 M NaCl to denature the DNA, neutralized with 0.5 M Tris-HCl (pH 8.0)/1.5 M NaCl, and rinsed with 2×SSC (1×SSC=0.15 M NaCl/0.015 M sodium citrate, pH 7.0). The DNAs were fixed on the membrane by UV irradiation using a Stratalinker 1800 (Stratagene, Inc., La Jolla, Calif.). The ECL 3′-oligolabelling and detection system (Amersham, Arlington Heights, Ill.) was used for synthesis of labeled oligonucleotide probes, hybridization, and signal detection. The oligonucleotide sequences used to detect each point mutation were (substituted bases are shown as upper case letters):  
                                                   TABLE 5                           Oligonucleotide Probes                    Point Mutation   Oligonucleotide                            G93R mutation   gtctgaaaCggtgggat                   (SEQ ID NO:28)                       I105T mutation   acttctggactaCtatgg               (SEQ ID NO:29)                       S65C mutation   atcatgagTgtcgccgt               (SEQ ID NO:30)                      
 
         [0044]     For signal detection, each oligonucleotide was labeled with fluorescein-11-dUTP using terminal deoxynucleotidyl transferase according to the manufacturer&#39;s instructions (Amersham Ltd., Arlington Heights, Ill.). The membranes were prehybridized in 5×SSC, 0.1% Hybridization buffer component, 0.02% SDS, 5% LiquidBlock at 42° C. for approximately 2 hours. Labelled oligonucleotide probes were added to individual bags containing the membranes and prehybridization buffer and incubated at 42° C. overnight. The blots were washed twice with 5×SSC, 0.1% SDS for 5 minutes at room temperature. Stringency washes for hybridization with oligonucleotides having the sequence of SEQ ID NO: 30 or 28 were performed twice in 0.2×SSC/0.1% SDS for 15 minutes at 42° C. Membranes probed with an oligonucleotide having the sequence of SEQ ID NO:29 was washed twice under less stringent conditions (0.5×SSC/0.1% SDS, 15 minutes at 42° C.). Detection of a fluorescent signal was performed according to standard methods.  
       EXAMPLE 3  
     Characterization of Probands  
       [0045]     The mean age of the twenty probands was 44±11 years (range 27-62 years); thirteen (65.0%) were men and seven (35.0%) were women. Eleven had iron overload. One had hepatic cirrhosis, two had diabetes mellitus, four had arthropathy, and two had hypogonadotrophic hypogonadism. One proband also had hereditary stomatocytosis, another had beta-thalassemia trait, a third had ethanol intake &gt;60 g daily, and a fourth had porphyria cutanea tarda. No proband had evidence of excess oral or parenteral iron intake, or of viral hepatitis B or C. At diagnosis of hemochromatosis, evaluation for common HFE mutations revealed that eleven probands were C282Y heterozygotes, five were H63D heterozygotes, and four did not inherit C282Y or H63D.  
         [0046]     The mean age of the initial 176 control subjects was 52±15 years (range 18-86 years); 79 (44.9%) were men and 97 (55.1%) were women. There was no significant difference in the mean ages of men and women. Frequencies of HFE genotypes among the control subjects are shown in Table 6. These values are similar to those previously reported from normal persons from the same geographic area.  
                                 TABLE 6                           Frequencies of HFE Genotypes in Alabama Subjects.                    Hemochromatosis Probands                   with “Atypical” HFE   Normal Control           HFE Genotype   Genotypes, % (n)   Subjects, % (n)                       wt/wt   15.00 (3)        60.23 106)           C282Y/wt   45.00 (9)    13.06 (23)           H63D/wt   20.00 (4)    15.34 (27)           S65C/wt   5.00 (1)   1.14 (2)           C282Y/S65C   5.00 (1)   0           C282Y/G93R   5.00 (1)   0           H63D/1105T   5.00 (1)   0           H63D/C282Y   0    6.82 (12)           H63D/H63D   0   3.41 (6)                         Results are expressed as percentage (n). The wild-type (wt) allele was defined as the HFE configuration in which the mutations C282Y, H63D, S65C, I105T, or G93R were not detected.             
 
       EXAMPLE 4  
     Identification of Novel HFE Mutations in Hemochromatosis Probands  
       [0047]     The following novel mutations (missense mutations) were identified in probands 1 and 2: exon 2, nt 314T→C (I105T), and exon 2, nt 277G→C (G93R), respectively (Table 7;  FIGS. 1 and 2 ). Probands 3 and 4 had a S65C mutation The S65C mutation has been observed in hemochromatosis patients but has not been deemed to be indicative of a disease state. In contrast, the data presented herein indicate that the S65C mutation is diagnostic of a disease state. This result is surprising in view of earlier observations. Other than C282Y or H63D, no HFE exon mutations were detected in the remaining sixteen of the twenty probands (Table 6). Nine probands were heterozygous for a base-pair change at intron 2, nt 4919T/C (SEQ ID NO:27); two probands were homozygous for this base-pair change. Heterozygosity for a base-pair change in intron 4 (nt 6884T→C) was detected only in probands 3 and 4, both of whom also inherited S65C. One proband was heterozygous for a base-pair change at intron 5, nt 7055A→G.  
         [0048]     Using dot blot methodology, heterozygosity for the S65C mutation was detected in two of 176 normal control subjects (Table 6). The G93R or I105T mutations were not detected in normal control subjects (Tables 6 and 8).  
       EXAMPLE 5  
     Association of Novel HFE Coding Region Mutations to C282Y and H63D and HFE Intron Alleles  
       [0049]     In proband 1, two mutations of exon 2 (H63D and I105T) were detected. After subcloning the genomic fragment, the subclones revealed that these mutations occurred on separate chromosomes; this observation was confirmed by family studies indicating segregation of I105T  
                                                                                   TABLE 7                           Phenotypes and Uncommon HFE Genotypes in Alabama Subjects*                Age (years),   HFE       Transferrin   Serum Ferritin,   Hepatocyte   Phlebotomy,       Subject†   Sex   Genotype   HLA Type   Saturation, %   ng/mL   Iron Grade   Units                    Proband 1   52 M   H63D/I105T   A2, 3; B7, 7   62   868   2+   20       Proband 2†   40 M   C282Y/G93R   A2, 3; B7, 62   78   861   4+   34       Proband 3§   47 F   C282Y/S65C   A2, 32; B8, 44;   90   281   3+   37                   Bw4, 6; Cw5, 7       Proband 4**   81 F   S65C/wt   A2, 32; B14, 62   100   5,135   N.D.   37       Normal Control 1   28 M   S65C/wt   A2, 31; B35, 60   28   141   N.D.   N.D.       Normal Control 2   69 M   S65C/wt   A24, 26; B8,   42   747   2+   N.D.                   B37; Bw4, 6;                   Cw6, 5 (or 7)                 *Serum transferrin saturation, serum ferritin concentration, and percutaneous hepatic biopsy were performed before therapeutic phlebotomy was initiated. Reference ranges for these parameters are 15-45%; 20-300 ng/mL (men) and 20-200 ng/mL (women); and 0-1+, respectively. Iron depletion (serum ferritin ≦20 ng/mL) was induced by removing the indicated numbers of units of blood. None of these persons had evidence of hepatic          # cirrhosis, diabetes mellitus, hemochromatosis-associated arthropathy, hypogonadotrophic hypogonadism, other endocrinopathy, or cardiomopathy. N.D. = not done. The mutations indicated are exon 4, nt 845G→A (C282Y); exon 2, nt 187C→G (H63D); exon 2, nt 314T→C (I105T); exon 2, nt 277G→C (G93R); and exon 2, nt 193A→T (S65C). The wild-type (wt) allele was defined as an HFE allele in which the mutations C282Y, H63D, S6SC, I105T, or G93R were not detected.          †Countries of origin: Probands 1 and 2, England; Proband 3, Wales, England, and Americas (Cherokee); Proband 4, England and Ireland; Normal Control 1, England; Normal Control 2, The Netherlands.            ‡The father and sister of Proband 2 are presently undergoing therapy for hemochromatosis and iron overload, but their clinical and genetic data were unavailable.            §Proband 3 had porphyria cutanea tarda alleviated with therapeutic phlebotomy.            **Proband 4 had hereditary stomatocytosis unaffected by phlebotomy treatments. 37 units of blood were removed by phlebotomy before treatment was discontinued due to stroke apparently unrelated to anemia or iron overload (post-treatment serum ferritin 1,561 ng/mL). Her 59 year-old daughter (who does not have hereditary stomatocytosis) had transferrin saturation 42%, serum ferritin 62 ng/mL, HLA type A1, 32; B14, 15; Bw4, 6; Cw3, 8, and HFE genotype S65C/H63D.          # These data permitted assignment of the S65C mutation in this family to a haplotype carrying HLA-A32; linkage of S65C and HLA-A32 was also observed in the family of Proband 3.           
 
         [0050]                                                                                TABLE 8                           Frequencies of HFE Alleles in Alabama Subjects.                wt*   C282Y   H63D   S65C†   I105T   G93R                        Hemochromatosis Probands with   0.500   0.275   0.125   0.050   0.025   0.025       “Atypical” HFE Genotypes (n = 20)       Normal Control Subjects (n = 176)   0.750   0.099   0.145   0.006   ‡   ‡                 The wild-type (wt) allele was defined as an HFE allele in which the mutations C282Y, H63D, S65C, I105T, or G93R were not detected.            †S65C was detected in 2 of 22 (0.091) proband chromosomes and in 2 of 266 (0.0075) control chromosomes that did not bear the C282Y, H63D, S65C, I105T, or G93R mutation.            ‡Based on this data set, the frequency of the I105T and G93R HFE alleles is estimated to be &lt;0.0028, respectively.               
 and H63D ( FIG. 1 ). In proband 2 (HFE genotype C282Y/G93R), RT-PCR analysis (with subsequent subcloning and sequencing) revealed that these HFE mutations occurred on separate chromosomes. Family studies of proband 3 (HFE genotype C282Y/S65C) indicated that the C282Y and S65C HFE alleles segregated independently, establishing their occurrence on separate chromosomes (Table 7,  FIG. 3 ). 
 
         [0051]     In proband 1 (HFE genotype H63D/I105T), the I105T mutation was co-inherited with HLA-A3, B7. In probands 3 and 4 and their respective families, S65C was inherited on the same chromosome as HLA-A32, indicating that HLA-A32 is a marker for chromosomes bearing the S65C mutation, and individuals with HLA-A32 have an increased risk for developing hemochromatosis. The G93R mutation is associated with HLA-A2, and individuals with that haplotype have an increased risk for developing hemochromatosis. The I105T mutation is associated with HLA-A3, e.g., HLA-A3, B7, and individuals with that haplotype have an increased risk for developing hemochromatosis. Among twenty probands tested, the nucleotide polymorphism in intron 4 (nt 6884T→C) was detected in probands 3 and 4, both of whom also had S65C. Subjects that tested positive for the S65C mutation all were found to have the intron 4 (6884T→C) mutation, including two probands (3 and 4), their families, and two normal controls.  
       EXAMPLE 6  
     HFE Coding Region Mutations and Clinical Phenotype  
       [0052]     The 110ST and G93R mutations were associated with a hemochromatosis clinical phenotype in probands 1 and 2 who also inherited H63D and C282Y, respectively. Proband 3 had clinical evidence of hemochromatosis, iron overload, and porphyria cutanea tarda associated with compound heterozygosity for C282Y and S65C. Proband 4 had severe iron overload associated with heterozygosity for S65C and co-inheritance of hereditary stomatocytosis (Table 7). The sister of proband 1 (HFE genotype I105T/wt) was not completely evaluated for hyperferritinemia ( FIG. 1 ). Otherwise, family members of probands who were heterozygous for novel HFE mutations described herein had little or no evidence of abnormal iron parameters, a hemochromatosis phenotype, or of iron overload (Table 7 and 9;  FIGS. 1 and 3 ). Normal Control 1 who had HFE genotype S65C/wt had a  
                                                                                   TABLE 9                           Hemochromatiosis (HC) Family study/patent                                        Diagnosis/                       intron 4   Tf sat**   Ftn**   Hepatocyte       Subject/Age/Sex   HLA Type   exon 2   exon 4   5636 bp   %   ng/ml   Iron grade                    Proband 1/57M (201)   A2, 3; B7, 7   H63D/H, 1105T/1   Wt   T   62   868   HC/2+       brother/45M(204)       H63D/H   Wt   T*   31   186       sister/50F(203)   A3, 3: B7, 7   1105T   Wt*   T*   37   576       daughter/31F(301)   A32, 68 ; B7, 44   1105T/1   Wt*   T*   31   56       son/27M(302)   A2, 68; B7, 44   H63D/H   Wt*   T*   33   44       Proband 2/40M   A2, 3; B7, 62   G93R/G   C282Y/C   T   78   861   HC/4+       Father       Wt   C282Y/Y*   T*           HC       Sister       G93R/G   C282Y/C*   T*           HC       Proband 3/47(201)   A2, 32; B8, 44   S65C/S   C282Y/C   T/C   90   281   HC/3+       brother/45M(202)   A2, 32; B44, 51   S65C/S   Wt   T/C   33   42       mother/81F(102)   A2, 2; B8, 51   Wt   C282Y/C   T*   NT   NT       sister/33F(204)   A2, 7; B27, 51   Wt   Wt   T*   NT   NT       brother/35M(203)   A2, 7; B27, 51   Wt   Wt*   T*   NT   NT       sister       Wt   C282Y/C*   T*       sister       S65C/S   Wt*   T/C*       Proband 4/81F   A2, 32; B14, 62   S65C/S   Wt   T/C   100   S135   HC +                                   stomatocytosis       daughter/59 •     A1, 32; B14, 15   H63D/H, S65C/S   Wt*   T/C   42   62       Control 1/28M   A2, 31; B35, 60   S65C/S   Wt   T/C   28   141       Control 2/69M   A24, 26; B8, 37   S65C/S   Wt   T/C   42   747   2+                 *RE cut            **normal (15-45%)            ***20-300 ng/ml (men)            2C-200 ng/ml (women)             
 
 normal iron phenotype (Table 7). Normal Control 2, who also had the HFE genotype S65C/wt, had hyperferritinemia and mildly increased stainable hepatocellular iron deposition, but had no symptoms or other objective findings attributable to iron overload (Table 7). These data indicate that S65C heterozygosity is associated with abnormal iron parameters. 
 
       EXAMPLE 7  
     HLA Gene Linkage  
       [0053]     In the family of proband 1, the I105T mutation was linked to HLA-A3, B7, markers which are often linked to the C282Y mutation and its ancestral haplotype. HLA-A3, B7 is also significantly more common among C282Y-negative hemochromatosis probands than in normal control subjects tested. S65C was linked to HLA-A32 in probands 3 and 4 (and their respective families). The base-pair change in intron is 4 (nt 6884T→C) was detected only in probands who inherited the S65C mutation. These data indicate that an intron 4 mutation (nt 6884→C) is a marker for chromosomes bearing the S65C HFE allele. Three of four probands who inherited mutated HFE exon 2 mutations described herein also inherited the C282Y or H63D mutations on separate chromosomes. In a fourth proband, the co-inheritance of S65C heterozygosity and hereditary stomatocytosis was associated with severe iron overload.  
         [0054]     Altered interactions of transferrin receptor, transferrin, and C282Y and H63D mutant HFE protein contribute to the pathology of hemochromatosis. The S65C, G93R, and I105T mutations are located within the α1 domain: in the α1 helix of the HFE class I-like heavy chain (I105T and G93R), and at the tip of the A chain loop of the β-pleated sheet (S65C). These mutations affect the overall structure of the HFE gene product, and specifically affect the salt bridge between residues H63 and D95. The I105T substitution also inhibits proper folding of the α1 domain of the HFE gene product, and specifically affects the hydrophobicity of the hydrophobic F pocket.  
         [0055]     Other embodiments are within the following claims.