bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of a residual group in low‐molecular‐weight allergoids of Artemisia vulgaris pollen on their allergenicity, IgE‐ and IgG‐binding properties
Authors: Ćirković T. , Gavrović‐Jankulović M. , Prišić S. , Jankov R. M. , Burazer L. , Vučković O. , Šporčić Z. , Paranos S.
Published: March 2003

Background: Reaction of ε‐amino groups of lysine with potassium cyanate, maleic, or succinic anhydride leads to allergoids of low molecular weight. No study has been performed to compare their properties and investigate the influence of a residual group on allergenicity and human IgE‐ and IgG‐binding of these derivatives.

Methods: Allergoids of a pollen extract of Artemisia vulgaris were obtained by means of potassium cyanate, and succinic and maleic anhydride. Biochemical properties were investigated by determination of amino groups, enzyme activity, isoelectric focusing IEF and SDS–PAGE. IgE‐ and IgG‐binding was determined using immunoblots and ELISA inhibition. Allergenicity was investigated by skin prick tests (SPT) on a group of 52 patients, of which 6 were control subjects, 30 were patients with no previous immunotherapy (IT), and 16 were patients undergoing immunotherapy.

Results: The same degree of amino‐group modification (more than 85%), residual enzyme activity (less then 15%), IEF, and SDS–PAGE pattern were noted. In the immunoblots of IgE‐binding, there was more pronounced reduction in the succinyl and maleyl derivatives than in the carbamyl one. IgG‐binding was less affected by carbamylation than by acid anhydride modification. The SPT showed that the succinylated derivative had the most reduced allergenicity (98% showed a reduced wheal diameter when tested with the succinyl derivative, 87% with the maleyl allergoid, and 83% with the carbamyl allergoid). The most significant difference among allergoids could be seen in the group of patients with high skin reactivity (83% of patients showed no reaction to the succinyl derivative when compared to the value of 28% for the carbamyl derivative or 22% for the maleyl derivative).

Conclusions: According to our results, all three modification procedures yielded allergoids with a similar extent of modification. No single biochemical parameter investigated in the study could predict the degree of reduced allergenicity in vivo. The most reduced allergenicity was seen in the succinyl derivative while the preservation of IgG binding epitopes was of the highest degree for the carbamyl derivative.
Pets in the home and the development of pet allergy in adulthood. The Copenhagen Allergy Study
Authors: Linneberg A. , Nielsen N. H. , Madsen F. , Frølund L. , Dirksen A. , Jørgensen T.
Published: March 2003

Background: The aim of the study was to investigate the association between exposure to cat and dog in the home and the development (incidence) of IgE sensitization to cat and dog.

Methods: Participants in a population‐based study of 15–69‐year‐olds in 1990 were invited to a follow‐up in 1998. Serum IgE antibodies against common inhalant allergens was assessed in 734 subjects (participation rate 69.0%) on two occasions 8 years apart. Information about current or previous keeping of cats and dogs in the home was obtained in a questionnaire at baseline.

Results: A cat in the home currently was significantly associated with the development of IgE sentisization to cat (adjusted odds ratio 8.4, 95% confidence interval (CI) 1.7–42.7). Moreover, an atopic predisposition in terms of IgE sensitization to allergens other than cat at baseline was an independent risk factor for the development of IgE sensitization to cat. A dog in the home was not significantly associated with the development of IgE sensitization to dog.

Conclusions: In this adult population, exposure to a cat in the home increased the risk of developing IgE sensitization to cat. More prospective data are needed on this issue.
New plant‐origin food allergens
Authors: Pastorello E. A. , Pravettoni V. , Calamari A. M. , Banfi E. , Robino A. M.
Published: March 2003

Plant‐origin foods, especially nuts and seeds, are the most important sources of food allergic reactions. An important characteristic is the quantitative and qualitative variability of their content in allergenic molecules, depending on plant growth, ripening, environmental stresses or industrial processing. In this review we will focus on newly identified allergens. Recent research have characterized and extensively studied their biochemistry, structure and immunological properties.
Impact and modulation of nasal obstruction
Authors: Horak F.
Published: March 2003

Nasal obstruction, the leading symptom of allergic rhinitis, results from the combined activity of early‐ and late‐phase allergic reactions. Desloratadine inhibits both early‐ and late‐phase inflammatory mediators in vitro. Thus, double‐blind, placebo‐controlled, randomized, crossover trials were conducted to assess the efficacy of desloratadine against nasal obstruction, measured objectively and subjectively, during controlled exposure of patients with seasonal allergic rhinitis to allergen. Positive results were obtained in three single‐dose studies; desloratadine 5 mg resulted in a greater improvement from baseline than did placebo in the total symptom score and the nasal obstruction symptom score (P ≤ 0.02). Desloratadine was more effective than placebo in a multiple‐dose study; desloratadine 5 mg was given once daily for 7 days, and a 6‐h allergen challenge was administered at the end of treatment compared with placebo. Desloratadine treatment was associated with less deterioration from baseline in the mean nasal airflow (P < 0.05) and in the mean severity score for the symptom of nasal obstruction (P < 0.03). Desloratadine significantly reduces the severity of nasal obstruction in patients with seasonal allergic rhinitis.
Pattern of central nervous system anomalies in a population with a high rate of consanguineous marriages
Authors: Al‐Gazali Li , Sztriha L , Dawodu A , Bakir M , Varghese M , Varady E , Scorer J , Abdulrazzaq Ym , Bener A , Padmanabhan R
Published: March 2003

Nine thousand six hundred and ten births were prospectively studied in the three major hospitals in Al‐Ain, United Arab Emirates (UAE) between October 1995 and January 1997. Babies suspected of, or diagnosed, as having central nervous system (CNS) abnormalities were evaluated by a neonatologist, a clinical geneticist and a pediatric neurologist. Brain computerized tomography/magnetic resonance imaging (CT/MRI) was performed on all babies suspected of having CNS abnormalities. In addition, metabolic screening and chromosome analysis were also performed when indicated. Of the 225 babies with congenital anomalies identified, 31 had CNS abnormalities (3.2/1000). Syndromic abnormalities of the CNS were present in 13 cases (42%), chromosomal abnormalities in one case (3.2%) and the rest included: neural tube defect (NTD) in 11 cases (36%), holoprosencephaly in two cases (6.4%) and hydrocephalus in four cases (12.9%). Detailed analysis of the syndromic types revealed that out of the 13 cases, 12 were inherited as autosomal recessive (AR) and in one case the inheritance was undetermined. Consanguinity with high level of inbreeding was present in 12 cases and the majority of the syndromes identified were extremely rare. The study indicates that CNS anomalies are fairly common in the UAE, particularly, the recessive syndromic types. Careful and detailed analysis of such anomalies is required so that accurate genetic advice can be given.
Family physicians’ perspectives on genetics and the human genome project
Authors: Fetters Michael D. , Doukas David J. , Luan Dinh Phan K.
Published: March 2003

The objective of the study was to determine family physicians’ attitudes and beliefs about human genetics research and the human genome project (HGP). The design of the study involved qualitative, semi‐structured interviews. Primary variables of interest included family physicians’ training; their attitudes about the HGP; requests for genetics counseling; and their approaches to counseling requests. The setting was a medium‐sized, Midwest, US city. The participants were 16 university‐affiliated, community‐based family physicians. For contents analysis, we used a coding scheme to identify illustrative themes and subthemes. While most of the family physicians reported familiarity with genetics and the HGP, and experiences with counseling requests, nearly all (15) reported little training in genetics counseling. Four major themes were identified: 1) impact on clinical care; 2) educational issues relevant to genetics and the HGP; 3) ethical concerns; and 4) family medicine responsibilities. These family physicians do not perceive genetics as having a substantial impact on their practice, but do expect major clinical changes in the future. Many feel there have been inadequate educational opportunities to learn about genetics, and some indicate reluctance to invest in self‐education until genetic problems become more clinically relevant. These practitioners envision a role for family medicine the specialty to shape priorities in genetics research.
FISH analysis with locus‐specific probes in sperm from two translocation carrier men
Authors: Durak Beyhan , Hakan Özön Yavuz , Özdemir Muhsin , Artan Sevilhan , Basaran Nurettin , Basaran Seher , Özkinay Cihangir
Published: March 2003

Meiotic segregation of normal and derivative chromosomes was analysed in sperm samples from two balanced reciprocal translocation carrier men by use of dual‐colour fluorescence in situ hybridisation (FISH) technique. The translocations were t(4;8)(p15;p12) and t(15;22)(q(23;q13.2), and the digoxigenin‐labelled FISH probes were specific to either the translocated or centric segments of the chromosomes involved in the translocations. A total of 1000 spermatozoa for each probe were analysed and the modes of segregation were described on the basis of signals in each sperm cell. The mean frequency of alternate and/or adjacent‐1 (adj‐1) segregation types was 69.47%, whereas they were 30.51 and 78.70% for the adjacent‐2 (adj‐2) and alternate/adj‐2 segregation types, respectively. This study illustrated that FISH is a valuable technique for analysing the meiotic segregation products of the heterozygotes in respect to aneuploidy risk.
Identification of three novel mutations in the insulin receptor gene in type A insulin resistant patients
Authors: Riqué Susanna , Nogués Carme , Ibàñez Lourdes , Victoria Marcos María , Ferragut Juan , Carrascosa Antonio , Potau Neus
Published: March 2003

Type A insulin resistance syndrome is characterized by the association of ovarian hyperandrogenism, acanthosis nigricans, and severe insulin resistance. We have identified three novel mutant alleles of the insulin receptor gene in 3 patients with type A syndrome, a severe form of insulin resistance. Two of the patients were sisters (A1, A2), 1 of them was a compound heterozygote for a mutation at the 3′‐splice acceptor site of intron 21 (AG→AA), and a missense mutation Val140Leu in exon 2. Her sister was a simple heterozygote for the 3′‐splice acceptor mutation. The third patient (A3) was heterozygous for the missense mutation Ala1028Val in exon 17, in the consensus sequence for ATP binding.
Molecular genetic testing for familial hypercholesterolemia: spectrum of LDL receptor gene mutations in the Netherlands
Authors: Lombardi M Paola , Redeker Egbert Jw , Defesche Joep C , Kamerling Sylvia Wa , Trip Mieke D , Mannens Marcel Mam , Havekes Louis M , Kastelein John Jp
Published: March 2003

Mutations in the LDL receptor are responsible for familial hypercholesterolemia (FH). At present, more than 600 mutations of the LDL receptor gene are known to underlie FH. However, the array of mutations varies considerably in different populations. Therefore, the delineation of essentially all LDL receptor gene mutations in a population represents a prerequisite for the implementation of nation‐wide genetic testing for FH. In this study, the frequency and geographical distribution of 13 known mutations were evaluated in a cohort of 1 223 FH patients. We identified 358 mutation carriers, representing 29% of the FH cohort. Four mutations (N543H‐2393del9, 1359−1 G→A, 313+1 G→A and W23X) occurred with a relatively high frequency, accounting for 22.4% of the entire study cohort. Two of these common FH mutations (N543H‐2393del9 and 1359−1 G→A) showed a preferential geographic distribution. Second, to further expand the array of LDL receptor gene mutations, we conducted mutation analysis by denaturing gradient gel electrophoresis (DGGE) in 141 children with definite FH. A mutation was identified in 111 patients, involving 16 new single base substitutions and four small deletions and insertions, which brings the number of different FH‐causing mutations in our country up to 61.  Our data indicate that an estimate of the prevalence of specific mutations, as well as the compilation of a database of all FH‐causing mutations in a given country, can facilitate selection of the most appropriate molecular diagnostic approach.
Association of the R485K polymorphism of the Factor V gene with poor response to activated protein C and increased risk of coronary artery disease in the Chinese population
Authors: Le Wei , Yu Jin‐De , Lu Lin , Tao Rong , You Bei , Cai Xu , Cao Wen‐Jun , Huang Wei , He Ru‐Min , Zhu Ding‐Liang , Chen Zhu , Gong Lang‐Sheng
Published: March 2003

Inherited predisposition to thrombosis contributes to the initiation and progression of coronary artery disease (CAD). The present study was designed to explore the relationship between genetic variation of coagulation factor V and occurrence of CAD.  A total of 141 unrelated patients with CAD and 175 healthy controls were analyzed by polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE) for variation detection in all 25 exons of the factor V gene. Among the study subjects, 55 CAD patients and 73 controls were evaluated at random for response to activated protein C (APC) by Coatest APC resistance test.  Polymorphisms in exon 4, 10, 13 and 16 of factor V gene were documented [642G→T(S156), 1628→A(R485K), 4070A→G(H1299R) and 5380G→A(V1736M), respectively]. The study also identified a novel polymorphism 327A→G in exon 2 which did not alter the amino acid residue. Leiden mutation (R506Q) was not detected in any of our 316 subjects. Among the five polymorphisms, the allele frequency of 1628G→A was significantly different between the CAD patients and the controls (0.36 vs. 0.21, p<0.05). Subjects homozygous or heterozygous for the A allele of 1628G→A polymorphism had lower normalized APC ratios than those with the GG genotype in the CAD group (1.16±0.13 and 1.18±0.23 vs. 1.36±0.33, p<0.05) and in the controls, indicating that A1628 allele was associated with a poor response to APC.  We conclude that the 1628G→A (R485K) polymorphism of factor V is associated with a poor response to APC and increased risk for CAD.
Recent advances in the molecular basis of inherited photoreceptor degeneration
Authors: Clarke Geoff , Héon Elise , McInnes Roderick R
Published: March 2003

To date, 118 loci have been associated with photoreceptor degenerative disease. In this review, we will discuss recent advances in the identification of genes that cause progressive photoreceptor cell death when mutated. We will focus on 12 genes isolated within the last two years that have been shown to be photoreceptor‐specific, or that have provided insight into photoreceptor biology and the mechanisms of photoreceptor cell death. To aid in understanding the biologic basis for these diseases, we also briefly review photoreceptor biology. Finally, we report on recent advances towards the treatment of these disorders.
Genetic testing, ethical concerns, and the role of patent law
Authors: Caulfield Timothy A , Gold E Richard
Published: March 2003

This article examines the changing debate over gene patenting and the possible connection between patent law and the ethical and policy concerns associated with the use of genetic testing technologies (e.g. the premature implementation and inappropriate marketing of genetic tests). Arguably, patent law helps to form the market forces that lead to these concerns. It is suggested that existing safeguards fail to control these concerns because of, for example, a lack of provider knowledge and an absence of an adequate regulatory framework. While patent law can be associated with a number of ethical and policy concerns, the article also suggests that patent law may have a positive role in reducing them. Patent law provides policy makers and the public with a focal point – the patent holder – upon which to attach accountability for ethical and legal conduct. The article concludes by inviting policy makers to consider the ways in which patent law could be modified in order to optimize its constructive influence.
Maternally inherited hearing impairment
Authors: Van Camp Guy , Smith Richard Jh
Published: March 2003

Mitochondria are intracellular organelles responsible for the majority of a cell's energy production. They have their own small maternally inherited genome which, when mutated, can give rise to a large spectrum of diseases. The phenotype most commonly includes neurological and muscular symptoms, although hearing impairment is an additional feature in some mitochondrial syndromes. Often, syndromic mutations affect only a fraction of all mitochondrial DNA molecules, a condition referred to as heteroplasmy. It is believed that the degree of heteroplasmy in different tissues contributes to the phenotypic heterogeneity that is a hallmark of these syndromes.  Five homoplasmic mutations leading to nonsyndromic hearing impairment have been reported (1555A→G, 7445A→G, 7472insC, 7510T→C, 7511T→C). The 1555A→G is in the 12S rRNA gene, and in some populations, appears to be a frequent cause of hearing impairment. Carriers of the mutation are abnormally sensitive to aminoglycoside‐induced ototoxicity even at ‘appropriate’ drug levels; in addition, even without aminoglycoside exposure, these persons can develop hearing impairment. The other four nonsyndromic mutations are located in the tRNASer(UCN) gene. In addition to hearing impairment, with two of these mutations (7445A→G, 7472insC), other symptoms can be present. In some patients, however, why these five mutations preferentially affect the inner ear, despite the crucial role of mitochondria in nearly all cells of the body, is unknown.
Novel deletional mutation of the MEN1 gene in a kindred with multiple endocrine neoplasia type 1
Authors: Kakizawa Tomoko , Sakurai Akihiro , Ikeo Yasuto , Ueno Ichiro , Hashizume Kiyoshi
Published: March 2003

MEN1 gene mutation in a Japanese kindred with multiple endocrine neoplasia type 1 was examined. A heterozygous deletion involving 29 base pairs in exon 10 (1606del29) was identified in the proband, and the same deletion was found in the affected family members. Most previously reported germline MEN1 gene mutations are nucleotide substitutions and small insertions/deletions, and a large deletion is rare. The hairpin structure mediated by an incomplete palindromic sequence at deletion termini is the most likely mechanism to be associated with the deletion in the present family.
Low‐density lipoprotein receptor gene mutations in a Southeast Asian population with familial hypercholesterolemia
Authors: Khoo Kl , Van Acker P , Defesche Jc , Tan H , Van De Kerkhof L , Heijnen‐van Eijk Sj , Kastelein Jjp , Deslypere Jp
Published: March 2003

The aim of this study was to detect mutations in the genes coding for the low‐density lipoprotein receptor and apolipoprotein B in patients of Southeast Asian origin with clinically diagnosed familial hypercholesterolemia (FH) and to relate these findings with the observed lower incidence of coronary heart disease in this part of the world.  A total of 86 unrelated patients with FH were selected on clinical grounds, and complete DNA analysis of the low‐density lipoprotein (LDL)‐receptor and apolipoprotein B (apoB) genes by DGGE and DNA‐sequencing was performed. In the majority (73%) of the cohort studied, no mutations could be detected, even after extensive analysis of the LDL‐receptor and apoB genes. However, the 22 patients with a mutation had significantly more xanthomas and a higher incidence of coronary heart disease and levels of low‐density lipoproteins were also significantly different. There was no correlation between the type of the mutation and lipoprotein levels or clinical signs of atherosclerosis.  The fact that the majority of the FH patients studied had no detectable mutation and that this group had a significant milder phenotype, suggests the presence of a third gene in the Southeast Asian population, predominantly leading to a disorder resembling a milder form of FH. A similar, but less frequent, trait has recently been described in a number of European families
The clinical significance of fragile sites on human chromosomes
Authors: Sutherland GR , Baker E
Published: March 2003

Fragile X syndrome is now a well established common clinical entity and most of those who are aware of the condition probably know that it takes its name from a rare fragile site (FRAXA) on the X chromosome. This is the best known fragile site and its clinical significance is clear. Similar, but a little less known is FRAXE, a fragile site close to that associated with fragile X syndrome, but in this case associated with a mild form of non‐specific X‐linked mental retardation. These are the only two fragile sites that are unequivocally of clinical significance. A fragile site within the CBL2 oncogene on chromosome 11 has been mapped very close to the deletion breakpoint in a handful of patients with Jacobsen syndrome. It is doubtful that parents with FRA11B are at increased risk of having children with Jacobsen syndrome, but this cannot be ruled out.  The common fragile sites have been implicated in oncogenesis since shortly after their discovery in the early 1980s. While a couple of these are within genes that have been implicated in cancer it is unclear whether either the fragile sites, or the genes in which they are located are important in cancer. It may be that the common fragile sites are regions of genomic instability and that this instability is increased in malignant cells, analogous to the enhanced instability seen at microsatellite loci in a number of tumours. Since we all have the common fragile sites there is no suggestion that they give anyone an increased risk of developing malignant disease.  In dealing with patients who are found to have fragile sites, other than FRAXA, FRAXE and possibly FRA11B, considerable reassurance can be given that they are not at increased risk of having children with congenital disease or developing disease themselves because of their fragile sites.
The common mutations in the lipoprotein lipase gene in Italy: effects on plasma lipids and angiographically assessed coronary atherosclerosis
Authors: Arca M , Campagna F , Montali A , Barillà F , Mangieri E , Tanzilli G , Seccareccia F , Campa PP , Ricci G , Pannitteri G
Published: March 2003

The present study evaluated the role of the common lipoprotein lipase (LPL) mutations on the risk of dyslipidemia and coronary atherosclerosis in an Italian population. Cohorts of 632 patients undergoing coronary angiography, as well as 191 healthy controls, were screened by a combination of PCR and restriction enzyme digestion. In the pooled population, the frequencies of LPL D9N and N291S were 4.1%, with no homozygous carriers, whereas that of LPL S447X was 21% with 19.6% heterozygous and 1.4% homozygous carriers. Compared to non‐carriers, LPL N291S carriers showed higher plasma triglycerides (TG) (p<0.03) and increased risk of high TG phenotype (odds ratio [OR] 2.49, 95% CI 1.06–5.81; p<0.03). When this LPL mutation was associated with high body mass index (BMI) (>25 Kg/m2) or fasting, plasma insulin (>10.6 mU ml−1) significantly reduced HDL‐C levels were also observed. Carriers of the S447X mutation presented with higher HDL‐C concentrations (p<0.05) as compared to non‐carriers; they also showed a significantly reduced risk of high TG/low HDL‐C dyslipidemia (OR 0.34, 95% CI 0.12–0.99; p<0.05). The favourable effect of the LPL S447X variant was even more pronounced in lean subjects and in those with low insulin levels. No significant influence on plasma lipids by the LPL D9N was observed. None of LPL variants was a significant predictor of angiographically assessed coronary atherosclerosis. At most, the risk was borderline, increased in N291S carriers and possibly decreased in S447X carriers.
Sex determination: lessons from families and embryos
Authors: Ostrer H
Published: March 2003

Genetic studies in familial cases of sex reversal and in human embryos have contributed to the understanding of human sex determination and its disorders. For some heritable disorders of sex reversal, the gonadal phenotype was frequently overlooked until sex reversal was discovered fortuitously by chromosome analysis, often resulting in preventable complications. Within families, the phenotypes are variable and, in some instances, these can be explained by known genetic mechanisms. When a novel molecular marker is shared by family members affected with sex reversal, the level of confidence is higher that this marker may play a role in the development of the phenotype. The identification of pedigrees with sufficient power to generate significant linkage of disorder (lod) scores from genomewide screens can now lead to the identification of novel sex‐determining genes. Studies of the gonads of 46,XY human embryos have shown that SOX9 expression follows a pattern similar to that of SRY and, in both instances, stands in contrast to the expression observed in the mouse. Differences between human and mouse embryonic gonads have also been observed for the temporal expression of DAX1, suggesting that the mechanisms of action of SRY, SOX9, and DAX1 may vary between these and other species.
Distal limb malformations: underlying mechanisms and clinical associations
Authors: Sifakis S , Basel D , Ianakiev P , Kilpatrick MW , Tsipouras P
Published: March 2003

Congenital malformations of the extremities are conspicuous and have been described through the ages. Over the past decade, a wealth of knowledge has been generated regarding the genetic regulation of limb development and the underlying molecular mechanisms. Recent studies have identified several of the signaling molecules, growth factors, and transcriptional regulators involved in the initiation and maintenance of the apical ectodermal ridge (AER) as well as the molecular markers defining the three axes of the developing limb. Studies of abnormal murine phenotypes have uncovered the role played by genes such as p63 and Dactylin in the maintenance of AER activity. These phenotypes resemble human malformations and in this review we describe the underlying mechanisms and clinical associations of split hand/foot malformation and ectrodactyly–ectodermal dysplasia–cleft lip/palate syndrome, which have both been associated with mutations in the p63 gene.
Trisomy rescue by postzygotic unbalanced (X;14) translocation in a girl with dysmorphic features
Authors: Orellana C , Martínez F , Badía L , Millán JM , Montero MR , Andrés J , Prieto F
Published: March 2003

In this report we present the clinical features and molecular and cytogenetic findings in a female with partial trisomy 14q. Molecular and cytogenetic studies allowed us to determine that the extra 14q material (of paternal origin) was translocated postzygotically onto the maternal X chromosome. Consequently, only the derivative X chromosome was inactivated, although inactivation apparently did not spread over the entire chromosome 14q. This partial inactivation makes the present case unusual, giving rise to phenotypic features absent in other patients with partial trisomy 14q, typically restricted to the distal part of the chromosome.
Real‐time quantitative PCR analysis for α‐thalassemia‐1 of Southeast Asian type deletion in Taiwan
Authors: Sun Chien‐Feng , Lee Chien‐Hong , Cheng Shue‐Wei , Lin Mei‐Hui , Wu Tsu‐Lan , Tsao Kuo‐Chien , Chiu Daniel TY , Liou Jui‐Der , Chu Da‐Chang
Published: March 2003

Since homozygosity of the α‐thalassemia‐1 of Southeast Asian (SEA) type deletion results in hydrops fetalis, a novel protocol based on the real‐time quantitating polymerase chain reaction (PCR) technique has been developed to quantify the intact and aberrant α‐globin genes in adults. The ratio of the normal/SEA‐bearing α‐globin genes was expressed in cycle threshold (CT) values. Theoretically, a relative ratio of one to one was anticipated in individuals carrying the SEA type deletion. Twenty‐five heterozygous and 20 normal cases were analyzed retrospectively with this protocol. Data showed that the CT values for the intact α‐globin gene allele and the allele bearing the SEA type deletion in carriers were 28.74±1.49 and 26.46±2.05, respectively. Therefore, the ratio of normal/SEA type deletion‐bearing α‐globin genes in the carriers was 1.09±0.043. No ambiguous results were observed from other less common genotypes associated with α‐thalassemia, such as the Philippine type deletion. Based on the results, we concluded that this protocol could provide a rapid method to mass screen carriers with α‐thalassemia‐1 of SEA type deletion in this region.
Tandem duplication mosaicism: characterization of a mosaic dup(5q) and review
Authors: Rauen KA , Bitts SM , Li L , Golabi M , Cotter PD
Published: March 2003

Mosaicism for tandem duplications is rare. Most patients reported had abnormal phenotypes of varying severity, depending on the chromosomal imbalance involved and the level of mosaicism. Post‐zygotic unequal sister‐chromatid exchange has been proposed as the main mechanism for tandem duplication mosaicism. However, previous molecular analyses have implicated both meiotic and post‐zygotic origins for the duplication. We describe a newborn male who was originally diagnosed in utero with arrhythmia and tetralogy of Fallot. He had multiple dysmorphic features including telecanthus, blepharophimosis, high broad nasal bridge with a square‐shaped nose, flat philtrum, thin upper lip, down‐turned corners of the mouth, high‐arched palate, micrognathia, asymmetric ears, and long, thin fingers and toes. Karyotyping of peripheral blood lymphocytes showed mosaicism for a tandem duplication of part of the long arm of one chromosome 5: mos46,XY,dup(5)(q13q33)[6]/46,XY[45]. Fibroblast cultures had the same mosaic karyotype with a higher frequency of the dup(5) clone: mos46,XY,dup(5)(q13q33)[9]/46,XY[21]. Fluorescence in situ hybridization analysis with a wcp5 confirmed the chromosome 5 origin of the additional material. Parental karyotypes were normal indicating a de novo origin of the dup(5) in the proband. Molecular analyses of chromosome 5 sequence‐tagged‐site (STS) markers in our family were consistent with a post‐zygotic origin for the duplication. Therefore, mosaicism for tandem duplications can arise both through meiotic or mitotic errors, as a result of unequal crossing over or unequal sister‐chromatid exchange, respectively. Our review indicates that mosaicism for tandem duplications is likely under‐ascertained and that parental karyotyping of probands with non‐mosaic tandem duplications should be performed.
Acanthocytosis in a patient with homozygous familial hypobetalipoproteinemia due to a novel APOB splice site mutation
Authors: Hegele RA , Miskie BA
Published: March 2003

We report on acanthocytosis in a 31‐year‐old woman with homozygous familial hypobetalipoproteinemia due to a mutation affecting the splicing of the APOB gene encoding apolipoprotein B. Treatment with fat‐soluble vitamins was associated with arrest of the usually progressive neurological complications of this condition. However, the acanthocytosis – literally ‘thorny’ erythrocytes that result from abnormal membrane fluidity – persists despite treatment.
A CGH study of 27 patients with CHARGE association
Authors: Sanlaville D , Romana SP , Lapierre JM , Amiel J , Genevieve D , Ozilou C , Le Lorch M , Brisset S , Gosset P , Baumann C , Turleau C , Lyonnet S , Vekemans M
Published: March 2003

CHARGE association is a non‐random occurrence of congenital malformations including coloboma, heart disease, choanal atresia, retarded growth and/or retarded development, genital hypoplasia, ear anomalies and/or deafness. The cause of this association remains unknown. Various genetic mechanisms have been proposed, including a contiguous gene syndrome but, so far, no recurrent locus has been identified. To address this question, we decided to perform a comparative genomic hybridization (CGH) study on a cohort of 27 patients with CHARGE association and a normal standard karyotype. We found two chromosomal anomalies: a der(9)t(9;13) derived from a paternal translocation and a der(6)t(4;6) of unknown origin. This suggests that chromosome imbalances may well mimic CHARGE association. Therefore patients with CHARGE association must be carefully tested with classical and molecular cytogenetic techniques to detect a potential chromosome imbalance. It is expected that more stringent diagnostic criteria of CHARGE association could define a more homogeneous group of patients where a single genetic cause might be identified.
RMRP gene sequence analysis confirms a cartilage‐hair hypoplasia variant with only skeletal manifestations and reveals a high density of single‐nucleotide polymorphisms
Authors: Bonafé L , Schmitt K , Eich G , Giedion A , Superti‐Furga A
Published: March 2003

Mutations in the RMRP gene that codes for an RNA subunit of the MRP RNAse complex are the cause of cartilage‐hair hypoplasia (CHH; MIM 250250). We tested the hypothesis that recessive metaphyseal dysplasia without hypotrichosis (M1M 250460), a disorder presenting with short stature and metaphyseal dysplasia similar to CHH, but lacking hair anomalies, immunodeficiency and other extra skeletal features, might be allelic to CHH. We identified four mutation‐carrying alleles segregating with the skeletal phenotype in two unrelated boys and their parents. One allele carried the common Finnish mutation +70A → G; the remaining three carried +195C → T, +238C → T, and dupAAGCTGAGGACG at −2. Sequencing 120 alleles from a control group revealed an unusually high density of single‐nucleotide polymorphisms in and around the RMRP gene: the biological significance of this finding is unclear.

We conclude that recessive metaphyseal dysplasia without hypotrichosis is a variant of CHH, manifesting only as short stature and metaphyseal dysplasia. Precise diagnosis of this form of metaphyseal dysplasia is not without importance because of recessive inheritance with corresponding recurrence risk, as well as because of potential complications such as anaemia, susceptibility to infections and the increased likelihood of developing cancer. The short stature and metaphyseal changes associated with cone‐shaped epiphyses of the hands should raise the diagnostic possibility of a CHH‐related disorder that can then be confirmed by mutation analysis.
A patient with treatment‐resistant schizophrenia and cytochrome P4502D6 gene duplication
Authors: Kawanishi C , Furuno T , Kishida I , Matsumura T , Kosaka K
Published: March 2003

We describe a patient with treatment‐resistant schizophrenia who had a duplication in the cytochrome P450IID6 (CYP2D6) gene. This severely ill 71‐year‐old‐woman had responded poorly to several neuroleptics. Molecular genetic study revealed CYP2D6 gene duplication, which results in excessive activity of CYP2D6 that metabolizes various commonly used neuroleptics. The mutation may have contributed to treatment resistance in this case.
Genetic landmarks through philately: Woodrow Wilson ‘Woody’ Guthrie and Huntington disease
Authors: Innes AM , Chudley AE
Published: March 2003

This brief account of Woody Guthrie is instructive to clinical geneticists. It tells the story of one famous man's understanding of, and struggle with, Huntington's disease. The philatelic illustration depicts Woody Guthrie playing his guitar in the years before advancement of the disease.
LDL receptor mutation genotype and vascular disease phenotype in heterozygous familial hypercholesterolaemia
Authors: Brorholt‐Petersen JU , Jensen HK , Jensen JM , Refsgaard J , Christiansen T , Hansen LB , Gregersen N , Faergeman O
Published: March 2003

Patients with homozygous familial hypercholesterolaemia (FH) caused by receptor‐negative, low‐density lipoprotein (LDL) receptor gene mutations have higher concentrations of LDL‐cholesterol in plasma and earlier onset of cardiovascular disease (CVD) than patients homozygous for receptor‐defective, LDL receptor mutations. In contrast, it is uncertain whether the severity of atherosclerotic disease differs in heterozygous FH caused by receptor‐negative and receptor‐defective mutations. The present authors investigated the influence of LDL receptor mutation type on the clinical phenotype in 31 patients with heterozygous FH caused by the receptor‐negative, Trp23‐stop mutation and in 31 patients heterozygous for the receptor defective Trp66‐Gly mutation. Untreated levels of plasma LDL‐cholesterol and calculated cholesterol‐years score did not differ significantly between the two groups of patients. Detection of vascular disease was based on two approaches: (1) measurement of coronary calcification by spiral computed tomography (CT) scanning; and (2) ultrasonic measurement of carotid intima‐media thickness (IMT). Age was significantly correlated to the presence of coronary calcification, but controlling for relevant cofactors, there was no evidence that the receptor‐negative mutation caused more calcification than the receptor‐defective mutation. Furthermore, carotid IMT was significantly influenced by plasma concentrations of Lp(a) and triglycerides, as well as by age, sex and smoking status, but again, there was no statistically significant effect of LDL receptor gene mutational type. The similarity in vascular phenotypes was probably caused by a similar life‐long burden of LDL‐cholesterol in the two groups of patients.
Service provision of complex mutation analysis: a technical and economic appraisal using dystrophin point mutation analysis as an example
Authors: Nixon J , Cockburn D , Hopkin J , Seller A , Huson SM
Published: March 2003

Duchenne muscular dystrophy (DMD) results from mutations in the dystrophin gene. One‐third of cases arise from point mutations, which are heterogeneous and difficult to detect. The aims of this study of dystrophin point mutation analysis were to assess its technical feasibility in a routine diagnostic laboratory, and to estimate its costs and clinical benefits. The methods used were a laboratory based study using reverse transcription‐polymerase chain reaction (RT‐PCR) and a protein truncation test, and a mathematical model to estimate costs and clinical benefits. None of the cases analyzed had an identifiable dystrophin deletion or duplication. They were 12 males affected with DMD and two obligate female carriers; two female carriers of known dystrophin point mutations were also analyzed. Point mutations were detected in six out of 12 males, but in none of the female carriers. Assuming a sensitivity of 50% the model predicts significant clinical benefits of point mutation analysis over linkage analysis, including a reduction in the number of prenatal diagnoses (by 0.77 per family), terminations of pregnancy (by 0.18 per family), and terminations of unaffected fetuses (by 0.16 per family). The mean cost of point mutation analysis to prevent the termination of an unaffected fetus is $6220.
Gene conversion (655G splicing mutation) and the founder effect (Gln318Stop) contribute to the most frequent severe point mutations in congenital adrenal hyperplasia (21‐hydroxylase deficiency) in the Spanish population
Authors: Ezquieta B , Cueva E , Oyarzábal M , Oliver A , Varela J M , Jariego C
Published: March 2003

This study addresses the contributions of gene conversion and a founder effect to the distribution of the two most frequent severe point mutations of the 21‐hydroxylase (21OH) gene causing congenital adrenal hyperplasia: the 655G splicing mutation at intron 2, and Gln318Stop in a Spanish population. Direct and indirect analyses of segregated mutant and normal 21OH genes in 200 Spanish families (classic and nonclassic 21OH deficiency) were performed. Both mechanisms were found to contribute to different degrees to the defective investigated alleles. The 655G splicing mutation (62 alleles, 15.5%) seemed to be almost exclusively related to recent conversion events, whereas Gln318Stop (33 alleles, 8.3%) is more likely to be due to the dissemination of remotely generated mutant alleles. Other severe defective alleles, 8 bp‐deletion (13 alleles, 3.3%), 306insT (5 alleles, 1.3%), and gene deletions (43 alleles, 11%), as well as the mild mutation Val281Leu (120 alleles, 30%), also appear to be strongly associated with particular D6S273 alleles.

Although gene conversion contributes to the generation of severe 21OH alleles, the high frequency of some severe mutations in different geographic areas is consistent with a founder effect.
Genotyping of Israeli infertile men with idiopathic oligozoospermia
Authors: Madgar I , Green L , Kent‐First M , Weissenberg R , Gershoni‐Baruch R , Goldman B , Friedman E
Published: March 2003

Microdeletions of the long arm of the Y chromosome involving the azoospermia factor (AZF) region are associated with severe oligo‐ or azoospermia. Abnormal androgen receptor (AR) structure or function has also been implicated in male infertility. To assess the contribution of these genetic defects to male infertility, 61 Israeli men with severe oligo‐ (n = 15) or azoospermia (n = 46), were screened for Y chromosome microdeletions, and the AR‐(CAG)n repeat length. Fifty fertile Israeli men were similarly analyzed. PCR amplification of 20–54 simple tag sequences (STSs) located at Yq was used to determine the rate and extent of Y chromosome microdeletions. PCR with primers flanking the AR‐(CAG)n region and subsequent size fractionation on gradient acrylamide gels were used to determine AR‐(CAG)n length. Five azoospermic individuals (5/61–8.2% and 5/46–10.8% of azoospermic patients) displayed Y chromosome microdeletions. The mean CAG repeat number in infertile men was 18.6 ± 3.0 compared with 16.6 + 2.7 in fertile men (n = 50), a statistically significant difference (p = 0.003). Y chromosome microdeletions contribute to male infertility in our azoospermic population, and the mean length of the AR‐CAG is significantly longer in our infertile population than in fertile men.
Genetic polymorphisms of the apolipoprotein A‐IV in a Greek population and their relation to plasma lipid and lipoprotein levels
Authors: Miltiadous G , Hatzivassiliou M , Bashiardes E , Bairaktari E , Cariolou MA , Elisaf M
Published: March 2003

Apolipoprotein (apo) A‐IV is a protein component of triglyceride‐rich lipoproteins and high‐density lipoproteins (HDL). In this study, two common genetic polymorphisms of the apoA‐IV gene [codons 347(allele A and T) and 360 (allele 1 and 2)] were investigated in Greek patients with hyperlipidaemia and in healthy individuals matched for age, sex and smoking habits. In both study populations we evaluated the effect of these polymorphic sites on lipid and lipoprotein plasma levels and the body mass index (BMI). The frequencies of the 1/1 and 1/2 genotypes in codon 360 were 0.94 and 0.06 in hyperlipidemic patients and 0.92 and 0.08 in the control population, respectively. The frequencies of the A/A, A/T and T/T genotypes in codon 347 were 0.62, 0.34 and 0.04 in hyperlipidemic patients and 0.59, 0.33 and 0.08 in the control population, respectively. None of the above genotype frequency differences between the study populations reached statistical significance. The control population was not affected by any polymorphism of the apo A‐IV gene. Hyperlipidaemic patients, carriers of the allele 2 (1/2 genotype), had significantly lower plasma triglyceride levels than carriers of the allele 1 (p = 0.03). Genetic variation in codon 347 had no influence on lipid and lipoprotein plasma levels. None of the polymorphisms at codons 360 and 347 affected the BMI. In conclusion, this study describes for the first time the genotype frequencies for polymorphic sites in codons 360 and 347 of the apo A‐IV gene in a Greek population and suggests that the presence of the allele 2 is associated with lower plasma triglyceride levels in hyperlipidaemic patients.
The A1555G mtDNA mutation in Danish hearing‐impaired patients: frequency and clinical signs
Authors: Østergaard E , Montserrat‐Sentis B , Grønskov K , Brøndum‐Nielsen K
Published: March 2003

The A1555G mutation of the mtDNA is associated with both aminoglycoside‐induced and non‐syndromic hearing loss. The A1555G is relatively frequent in the Spanish and some Asian populations, but has only been reported rarely in other populations, possibly because of ascertainment bias. We studied 85 Danish patients with varying degrees of hearing impairment and found two patients with the A1555G mutation (2.4%). Neither had received aminoglycosides. Our study indicates that the mutation might not be uncommon in Danish patients with hearing impairment.
Diabetic flies? Using Drosophila melanogaster to understand the causes of monogenic and genetically complex diseases
Authors: Lasko P
Published: March 2003

Approximately three‐quarters of human disease loci have counterparts in the fruit fly Drosophila melanogaster. This model organism is therefore extremely valuable for using to understand the role of these loci in normal development, and for unravelling genetic pathways in which these loci take part. Important advantages for Drosophila in such studies are its completed genome, the unparalleled collection of mutations already in existence, the relative ease in which new mutations can be generated, the existence of convenient techniques for inactivating or overexpressing genes in dispensable tissues that are easily observed and measured, and the ability to readily carry out second‐site modifier genetics. Recent work in Drosophila on the insulin‐signaling pathway, a pathway of profound clinical importance, is reviewed as an illustration of how such research can provide fundamental insights into the functions of this pathway in regulating growth and development. Moreover, Drosophila research is now identifying heretofore unknown regulators of insulin signaling, as well as indicating novel functions for this pathway in suppressing benign tumor formation and regulating life span.
An unstable dicentric Robertsonian translocation in a markedly discordant twin
Authors: Lebo RV , Wyandt HE , Warburton PE , Li S , Milunsky JM
Published: March 2003

Karyotypes from independent amniocenteses reflected a rare, unstable, functionally dicentric Robertsonian translocation chromosome in most cells in male Twin B who grew more slowly than the chromosomally normal female sib (Twin A). Twin B's balanced de novo Robertsonian translocation dic(13;14)(p11.1;p11.1), present in 81% of cells, underwent recurrent centromeric fission in 6 out of 30 independent colonies that explains a balanced 46,XY,‐13,+fis(13)(p11.1),‐14,+fis(14)(p11.1) karyotype. Aneuploidy for chromosomes 13q or 14q was present in 5% of cells. Instability of the Robertsonian translocation was evident because nine of the 30 colonies (30%) grown from single amniocytes had metaphase cells with more than one chromosome complement. Although uniparental disomy was excluded and a targeted ultrasound was normal, the couple was advised of the uncertain but real risk of abnormalities in Twin B and the risk to Twin A of terminating Twin B. The pregnancy proceeded and at 31 weeks gestation Twin A was in the 33rd percentile for size and Twin B in the 1st percentile. At 32 weeks, chromosome analysis revealed a balanced 45,XY,dic(13;14)(p11.1;p11.1) karyotype in all of Twin B's newborn cord blood cells with no evidence of fission or aneuploidy. Selection against unbalanced mitotic products of the unstable, functionally dicentric chromosome in early fetal development is proposed to result in Twin B's highly discordant small birth size.