ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Previous studies have yielded evidence for a locus conferring susceptibility to schizophrenia and schizophrenia spectrum disorders on chromosome 6p24–22 in a sample of multiply affected Irish families. We tested for linkage between highly polymorphic chromosome 6p24–22 markers and narrowly defined schizophrenia in a sample of 19 Southern African Bantu-speaking families, a population known to have diverged in the last 2000 years. There is no evidence to support the linkage of markers in this region of chromosome 6 to schizophrenia in this population.

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The frequencies of HLA class I (HLA-A, B, C) and class 11 (HLA-DR, DQ) antigens were measured in 107 unrelated schizophrenic subjects and the results compared with 264 controls from south-east Scotland and a second control group of 133 individuals from north-east England. The expression of HLA-B35 was significantly reduced in the schizophrenic population compared to both control populations and these differences remained significant after correction for multiple testing. Linkage of schizophrenia and the major histocompatibility complex region of chromosome 6p was, however, excluded in a group of 17 families multiply affected with schizophrenia. Linkage was also excluded with several red cell antigens, red cell enzymes and plasma proteins. A negative association between the frequency of an HLA antigen and schizophrenia suggests that immune mechanisms may contribute to the aetiology of the disease in some subjects.

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The phenomenon of anticipation has received considerable interest recently, especially among researchers investigating the genetics of psychiatric disorders. Anticipation can involve an earlier age at onset, greater severity, and/or a higher number of affected individuals in successive generations within a family. There is some controversy concerning detection of age-at-onset anticipation, due to problems of sampling bias, which may account for the phenomenon by preferentially sampling eitherlater-onset parents orearlier-onset children. One source of bias that has not been explicitly investigated is differential age at interview between parent and child, such that parents have passed through more of the risk period than their offspring. We conducted a computer simulation study of affected parent–child pairs to determine whether, for realistic age-at-onset and age-at-interview distributions, this source of bias is a serious one. Our results show that the timing of diagnostic assessment can strongly affect the ascertainment of parent–child pairs, to produce a severely biased sample exhibiting apparent anticipation. Under realistic assumptions, an investigator may face a greatly increased risk of false positives (i.e. detecting anticipation when none exists). For example, a nominal 5% significance level may correspond to truepvalues as high as 50% or even approaching 100%. We conclude with an application to existing data on panic disorder.

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Neurobiological studies indicate a dysregulation of the dopaminergic and GABAergic neurotransmission in bipolar disorder. We examined two large families segregating bipolar disorder, for linkage with the genes encoding dopamine beta-hydroxylase, the dopamine transporter DAT1, the dopamine D2, D3 and D5 receptors, and the alpha-1, alpha-5 and beta-1 subunits of the GABAAreceptor. Under at least one diagnostic model one of the two families provided evidence to exclude linkage for theDAT1, DRD2, DRD3, DRD5, DBH, GABRA1andGABARB1genes but could not exclude theGABRA5locus. A second family excluded only theGABRA1andGABRA5loci at zero recombination and could not formally reject linkage at theDBH, DRD2, DRD3, DRD5, DAT1andGABARB1loci. Further analyses at these loci are warranted.

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We examined the hypothesis that apolipoprotein E (apoE) isoforms - besides their well-established role in the aetiology of early and late onset Alzheimer's disease (AD) - may be involved in the development of schizophrenia. We determinedapoEgenotypes in 98 schizophrenic patients and 98 sex and age matched controls. No significant difference inapoEallele frequencies were observed between schizophrenic patients, subpopulations of schizophrenics, or controls. There was also no difference in the mean age at onset depending on the number ofapoE ϵ4alleles found in the patients. Our data do not support an association between AD and schizophrenia based onapoEacting as a common denominator in the pathogenesis of both diseases.

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

We have examined 23 families multiply affected with schizophrenia for linkage to theFMR-1gene on the X chromosome. Alleles at theFMR-1CGG triplet repeat were analysed by the polymerase chain reaction, and methylation status at theFMR-1locus in individuals with evidence of expanded or unstable repeats was analysed by Southern hybridization. Two-point LOD score analyses with a range of X-linked single gene models and a non-parametric affected sib-pair method revealed no evidence for linkage. In one family, however, a fragile X premutation was found, and one individual with schizophrenia and developmental delay was a mosaic for the full and premutation. We conclude that although mutations within theFMR-1gene do not have a major aetiological role in schizophrenia in our collection of pedigrees, it is possible thatFMR-1mutations can modify the clinical phenotype of schizophrenia.

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Benign familial chorea (BFC) is a rare neurological disease with an autosomal dominant transmission. The disorder is characterized by its early onset in childhood, a non-progressive course of choreatic movements and the absence of intellectual impairment. There is one study describing an expanded (CAG)nrepeat in the geneIT15(Huntington) on chromosome 4p (causative for Huntington's chorea) in a family reported to have BFC that was diagnosed on the basis of onset and non-progressive course. We failed to find an expansion of the (CAG)nrepeats in an Austrian family having BFC. The three affected individuals of the family had 18–25 CAG repeats. These results indicate that the diagnostic criteria for BFC should include a normal result in the analysis of the (CAG)nrepeat region of the Huntington gene.

ISSN:0955-8829    

出版商:OVID    

年代:1996

数据来源: OVID