摘要:

We screened 110 DNA samples from carriers of β-thalassaemia, using the ARMS-PCR technique with primers for common Mediterranean mutations. Unidentified samples were subjected to a heteroduplex analysis with Universal Heteroduplex Generators covering the β-globin gene, followed by DNA sequencing. In total, 16 different mutations were detected, the most frequent being IVSI-110 (40%), followed by other common Mediterranean mutations (IVSI-1, IVSII-1, IVSI-6). Other mutations detected were of Lebanese, Turkish, Iranian, Kurdish, Bulgarian and Asian Indian origin. The most heterogeneous religious group seems to be the Sunni Muslims, with 13 mutations, while only 2 mutations were detected among the Christian Maronites. Results from this study are compared with those from other Mediterranean and neighbouring countrie

ISSN:0001-5652    

DOI:10.1159/000154419

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The deletion polymorphism, situated in intron 16, of angiotensin-converting enzyme (ACE) gene (17q23) has been observed to be associated with an increased risk for myocardial infarction and left ventricular hypertrophy in Caucasian populations. The homozygous genotype for the deletion allele (DD) has additionally been observed at greater frequencies in hypertensive individuals of African-American and Japanese origin. In a population-based study of a Sikh population, we compared the occurrence of the insertion/deletion polymorphism at the ACE gene in subjects with hypertension to those with normal blood pressure. The ACE deletion allele was observed with a greater frequency in hypertensive subjects than in the normotensive subjects (p < 0.0001). These findings raise the possibility that in some ethnic subgroups, variation in or near the ACE gene may contribute to the development, and severity, of hypertension.

ISSN:0001-5652    

DOI:10.1159/000154420

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

We undertook molecular and cytogenetic analyses in 25 families multiplex for autism and related disorders. Three of the multiplex families exhibited fragile X, and the affected offspring all exhibited CGG triplet repeat insertion mutations in the FMR-1 gene. One of these families contained an affected pair of monozygotic female twins. Both had similar-sized CGG triplet repeat expansions, but different phenotypic manifestations. One suffered from autism and the other from mild mental retardation and marked social anxiety. PCR and Southern hybridization analysis of the CGG repeat sequences characterizing fragile X A (Frax A) and E and the methylation status of FMR-1 showed no evidence of abnormal CGG repeat expansion or FMR-1 hypermethylation in the remaining 22 multiplex families. Moreover, there was no correlation between the Frax A or E (CGG)n repeat length with affected status, nor any association with the low-level (<3%) expression of cytogenetic fragility at Xq27 previously reported in these families. Our findings indicate that most instances of recurrence in families multiplex for autism and related disorders are not accounted for by Frax A and E. They also indicate that the phenotypic manifestations of Frax A may be influenced by stochastic, environmental and other biological factors.

ISSN:0001-5652    

DOI:10.1159/000154421

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Recent studies have shown that hereditary hemochromatosis (HH) is likely to be caused by homozygosity for a Cys282Tyr mutation in the HFE gene located 4.5 Mb telomeric to HLA-A. Population studies of this polymorphism are facilitated by the fact that the Cys282Tyr mutation creates a Rsal restriction site. We have studied the codon 282 (Cys/Tyr) polymorphism in different ethnic groups. In agreement with previous observations the Tyr allele appeared to be rare or absent in Asiatic (Indian, Chinese) populations. The highest allele frequency (7.5%) was found in Swedes. Saamis (2%) and Mordvinians (1.8%) had significantly lower frequencies of the Tyr allele. Comparisons with allele frequencies based on prevalence estimates of HH showed some disagreements with the RFLP data, particularly in Finns. The newly described HFE marker provides a new approach to the screening of HH as well as studies of the relationship between the HFE Tyr allele and different disorders including cancer.

ISSN:0001-5652    

DOI:10.1159/000154422

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Attempts were made to follow up results of a previous linkage study which suggested that a locus-modifying susceptibility to bipolar and related unipolar affective disorder might be present in the pericentromeric region of the short arm of chromosome 18. Twenty-three multiply affected pedigrees collected from Iceland and the UK were genotyped using three highly polymorphic microsatellite markers at D18S37, D18S40 and D18S44 which span the region implicated. Lod score analyses under the assumption of heterogeneity and non-parametric linkage analyses were performed. The total lod scores obtained were strongly negative, and analysis allowing for heterogeneity did not suggest that any subgroup of the families was linked. Model-free linkage analysis using extended relative pair analysis and MFLINK also failed to detect any evidence for linkage. Our study provides no support for the presence of a locus-modifying genetic susceptibility to bipolar affective disorder in the pericentromeric region of chromosome 18q11. Further analyses in independent samples should help to reveal whether our negative results are due to locus heterogeneity or whether the original results were false-positive.

ISSN:0001-5652    

DOI:10.1159/000154423

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Several lines of evidence suggest that autoimmune mechanisms might contribute to the development of schizophrenia. Important factors involved in immune responses in man include the human leukocyte antigens and components of the complement system. In the present study we attempted to confirm a positive association between a homozygous deficiency in complement factor C4B and schizophrenia as previously reported. We also determined parental genotypes in a subset of our schizophrenic patients to test the hypothesis of a genetic mechanism depending on the mother’s genotype. C4B deficiency was found in similar frequency among patients (n = 176) and controls (n = 145). There was also no increased frequency of C4B deficiency in the mothers of schizophrenic patients. Our study does not support a widespread or consistent association between a deficiency in complement component C4B and schizophreni

ISSN:0001-5652    

DOI:10.1159/000154424

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

We investigated the relation between hepatoglobin (Hp) polymorphism and plasma lipid levels in 913 Korean subjects. The distribution of Hp phenotypes did not show any significant differences between the healthy controls and the patients with cardiovascular disease. In the control group, however, the subgroup of ≧ 50-year-olds had a significantly higher Hp*l allele frequency than the subgroup < 50 years (p < 0.005). This was not seen in the patient group. Hp phenotypes were associated with levels of high-density lipoprotein cholesterol in the hypertensive group. The results indicate that Hp polymorphism, at least in the Korean population, does not predispose to the occurrence of cardiovascular disease

ISSN:0001-5652    

DOI:10.1159/000154425

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The inclusion of DNA polymorphism into paternity analysis represents a major advance since it allows one to achieve a high probability of exclusion. This is of particular importance in paternity cases in which the mother and the alleged father are close relatives. The purpose of this article is to demonstrate an approach to calculate the probability of exclusion and to compute the paternity index in case of father-daughter incest using data from multiallelic loci that can be obtained with a single locus probe. The global probability of exclusion achieved at a multiallelic locus, in cases of father-daughter incest, is lower than the one obtained when both parents are not relatives. The probability of exclusion of each mother-offspring pair is different from that obtained when the parents are not close relatives. Among mother-offspring pairs having the same genotype, the probability of exclusion is zero, and in such a condition, the locus is not informative. To obtain a high exclusion capability, it is necessary to analyze several independent loci in which both the mother and the child have different genotypes. Expressions to obtain the paternity index for all the possible combinations of mother-offspring-alleged father in cases of father-daughter incest are derived and discussed.

ISSN:0001-5652    

DOI:10.1159/000154426

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, that encompasses 250 kb of genomic DNA, cause cystic fibrosis. More than 5-10% of CF patients in most populations studied carry undefined mutations and hence intragenic CA repeats are important tools in genetic counselling. To date, polymorphic intragenic repeats have been found in introns 6a, 8 and 17b. We have identified a novel CA repeat within intron 1 of the CFTR gene that lies about 70 kb 5’ to intron 6a and so will be a useful additional diagnostic marke

ISSN:0001-5652    

DOI:10.1159/000154427

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The T102C polymorphism at the 5-hydroxytryptamine 2a receptor (5HTR2a) gene was studied in 101 Chinese male schizophrenics and 103 controls. Genotyping revealed a predominance of allele 1 among schizophrenics. This is in contrast to previous reports in Caucasians and Japanese which showed an association of allele 2 of this polymorphism with schizophrenia.

ISSN:0001-5652    

DOI:10.1159/000154428

出版商:S. Karger AG    

年代:1997

数据来源: Karger