摘要:

Catechol-O-methyltransferase (COMT) metabolizes catecholamines such as dopamine, noradrenaline and adrenaline. It exists as common high and low activity alleles in the population (determined by a valine 158 methionine polymorphism), and high red blood cell activity of COMT has previously been associated with schizophrenia. To examine the relationship between COMT and schizophrenia genetically, the transmission disequilibrium test was performed on 22 multiply affected Caucasian and Japanese families genotyped for val158met and a second, silent, polymorphism (C256G), using PCR based assays. The high activity val158 allele was transmitted from parents to the affected individuals more frequently than the low activity met158 allele, although this was not statistically significant. Combining this data with a previous study using Chinese family trios with schizophrenia (Liet al., 1996) gave a highly significant result (p= 0.0015). The G256 allele was also transmitted preferentially to the affected offspring, and this was statistically significant when schizophrenia, schizoaffective disorder and unspecified functional psychosis were included in the definition of the affected phenotype (p= 0.03). Overall, these findings may indicate an effect of COMT alleles on susceptibility to schizophrenia, or reflect linkage disequilibrium with a different causative polymorphism in the vicinity. Other reported associations of COMT with obsessive compulsive and rapid cycling bipolar disorder indicate that theCOMTgene may have complex and pleiotropic effects on susceptibility and symptomatology of neuropsychiatric disorders.

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The pathogenesis of schizophrenia might involve abnormal development of the human brain. Interleukin-1β is a cytokine implicated in the development of the central nervous system and therefore its gene is a candidate gene in schizophrenia. Polymorphisms within the coding sequence and the 3'UTR of theIL1β gene were searched for using PCR-SSCP. Two polymorphisms,1B-175/1B-173and1B-1765/1B-1763were found in addition to the previously publishedTaqI site. Furthermore, a mutant was found in codon 106 (exon 5) of theIL1β gene located next to the published polymorphism at theTaqI site and abolishing this site. This novel mutation encodes an Asp in place of an Asn and was only observed in one patient in our French population. Association studies were conducted with the polymorphisms1B-175/1B-173andTaqI. There was no allelic or genotypic association between either of the two polymorphisms and schizophrenia. In our population, there is no evidence that theIL1β gene is involved in schizophrenia.

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Previous findings of increased heterozygosity for histidinemia among schizophrenic patients make the histidase gene a plausible candidate for genetic studies in schizophrenia. In the present study, we used a tetranucleotide repeat polymorphism in intron 8 of the histidase gene to examine the possibility that the histidase gene contributes to the genetic component of schizophrenia. In a first sample of 161 patients and 128 controls, we found the 4 repeat allele to be in excess in the patients. In contrast, the 3 repeat allele was less frequent in patients. A second sample of 95 patients and 93 controls was utilized to test these hypotheses. However, both observations were not replicated. We therefore concluded that our results do not support an involvement of the histidase gene in the development of schizophrenia.

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Biochemical studies have shown that a proportion of schizophrenics have an abnormal fatty acid composition in their red blood-cell membrane phospholipids and it has been suggested that this might be due to altered levels of the enzyme phospholipase A2(PLA2). A recent report indicated that there was an association between schizophrenia and alleles of a poly-A repeat polymorphism close to the 5′ end of thePLA2gene. We report the analysis of this polymorphism in a series of 58 schizophrenic patients and 56 controls and find no evidence for allelic association.

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The prevalence of Fragile-X syndrome in those with learning disability has been reported. There is little agreement regarding the prevalence rate which varies between 0% and 16%. We report a study investigating the prevalence of Fragile-X syndrome in two institutions for those with learning disability, using DNA testing. We found a rate of 0.7%, which is one of the lowest recorded rates. We also found that physical signs could be used as a reliable discriminator to determine those likely to have the disorder. We conclude that indiscriminate mass screening of those with learning disability for the Fragile-X syndrome is probably not useful because, in adults, physical signs and a family history of learning disability can predict those likely to have the disorder.

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Attitudes toward predictive testing for Alzheimer's disease and knowledge about this disease were investigated in a group of medical and psychology students. Overall, knowledge was poor and their own chance of getting Alzheimer's disease was mostly perceived as small. About half the students thought the development of a predictive test for Alzheimer's disease important, while the other half held the opposite view. Considerable variability was also observed in the judgement of the (dis)advantages of such a test. Only a minority of the students would like to have had a predictive test themselves. Important arguments against a predictive test concerned the absence of a treatment for Alzheimer's disease and the emotional burden of a positive test result. Arguments in favour dealt with the ability to make plans for the future and to prepare oneself for the disease. The divergence in attitudes and opinions reflects the complexity of predictive testing for Alzheimer's disease. Stepwise regression revealed that knowledge about Alzheimer's disease and, to a lesser extent, risk perception are significant predictors of attitudes toward predictive testing. However, they only explain a small part of the variance in attitudes. Moreover, why attitudes are less positive when knowledge and perceived susceptibility increase is not clear.

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

To examine a possible association between debrisoquine 4-hydroxylase gene mutations and neuroleptic malignant syndrome, we assessed frequencies of wild type and A and B mutant alleles of theCYP2D6gene in 24 patients with a history of nuroleptic malignant syndrome, 50 patients with neuroleptic-treated schizophrenia but no history of neuroleptic malignant syndrome, and 50 healthy controls. Allele frequencies did not differ significantly between these groups. Homozygotes forCYP2D6Aand forCYP2D6B, which indicate a poor-metabolizer phenotype for the CYP2D6 substrate, were not detected among the neuroleptic malignant syndrome cases. This result indicates no excess of poor CYP2D6 metabolizers in neuroleptic malignant syndrome. The aetiology of neuroleptic malignant syndrome is not explainable in terms ofCYP2D6gene mutations.

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0955-8829    

出版商:OVID    

年代:1997

数据来源: OVID