Further evidence of no linkage between schizophrenia and the dopamine D3 receptor gene locus (original) (raw)
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Lack of association between schizophrenia and alleles in the dopamine D 3 receptor gene
Acta Psychiatrica Scandinavica, 1993
Dopamine receptor dysfunction has been implicated in the pathophysiology of schizophrenia. Schizophrenic patients (n = 76) and control subjects (n = 53) were examined for allele frequencies in a 2-allele BalI polymorphism, causing a serine-->glycine amino acid substitution in the coding sequence of the dopamine D3 receptor gene. No statistical significant differences of allele frequencies or genotype frequencies could be found between the two groups. Neither were there any significant relationships between allele frequencies and a number of clinical variables within the schizophrenic subsample. However, if not corrected for multiple testing, an association was found between homozygosity and positive response to neuroleptic drugs. The present study does not provide evidence that the BalI polymorphism in the dopamine D3 receptor gene is involved in the pathophysiology of schizophrenia. Further investigations with an increased number and variety of patients concerning response to neuroleptic drugs and expression of the receptor in human brain should be performed to definitively exclude this hypothesis.
No association between schizophrenia and homozygosity at the D3 dopamine receptor gene
American Journal of Medical Genetics, 1993
The D3 dopamine receptor gene is an important candidate gene for schizophrenia, since (because of its almost exclusive expression in the limbic system) it combines the dopamine receptor hypothesis with the limbic system hypothesis of schizophrenia. A BalI restriction fragment length polymorphism of the D3 dopamine receptor gene has been typed in 107 schizophrenic patients and 98 normal controls from Sichuan (China). With regard to alleles or genotypes, no significant differences were obtained between controls from Europe and China, between patients and controls, and between patient subgroups and controls. These results indicate a lack of association between schizophrenia and the D3 dopamine receptor gene in our sample. Our findings are at variance with reports of a significant excess of homozygosity at the D3 dopamine receptor gene in schizophrenic patients from Wales (United Kingdom) and Alsace (France). In conclusion, further studies will be needed with larger samples of patients from Wales and Alsace as well as with samples of different racial groups to prove or disprove the initial positive association between schizophrenia and genotypes of the D3 dopamine receptor gene. © 1993 Wiley-Liss, Inc.
American Journal of Medical Genetics, 1993
Using a case-control design, a reported association of schizophrenia with homozygosity at the dopamine D3 receptor gene locus was investigated in a group of patients (n = 53), with schizophrenia (DSM-III-R), and psychiatrically normal controls (n = 61), matched for ethnicity and area of residence. No significant differences in the distribution of alleles or genotypes between the two groups could be deteched. However, among patients with a family history of schizophrenia, as compared to controls without such family history, an association with allele 1 at this locus was noted (Odds ratio 12.4, C.I. 1.61, 96.35). © 1993 Wiley-Liss, Inc.
Genetic study of dopamine D1, D2, and D4 receptors in schizophrenia
Psychiatry Research-neuroimaging, 1994
receptor genes in the etiology of schizophrenia. A linkage analysis using the lod score method was performed in 37 families originating from France (n = 14) and from the Island of La Rkunion in the Indian Ocean (n = 23). No evidence of linkage between schizophrenia and genetic markers located at these loci was found. A simulation study was carried out to gauge the significance of these results. The conclusions of a nonparametric linkage test (i.e., the affected pedigree member method) were equally negative. For each genetic marker, an allelic association with the disease was also sought: 80 unrelated patients and 80 healthy control subjects were tested, and no significant association was found. These results, which are in agreement with those obtained by other groups, do not support the involvement of the dopamine D,, D,, and D, receptor genes in the pathogenesis of schizophrenia.
American Journal of Medical Genetics, 1997
Dopamine D3 receptor (DRD3) was demonstrated to have important implications in schizophrenia, because it binds antipsychotic drugs and is abundant in the limbic system of the brain. Several groups attempted to find an association between a serine-to-glycine polymorphism at codon 9 of the DRD3 gene (Ser9Gly) and schizophrenia; however, the results were inconsistent. We conducted a case-control association study in Han Chinese schizophrenic patients from Taiwan, to examine the relationship of this serine-to-glycine polymorphism and schizophrenia. We noted no significant differences of genotype distribution, allele frequencies, or homozygosity proportion of this polymorphism between schizophrenic patients (N ؍ 178) and controls (N ؍ 100). When patients were divided according to sex, or presence or absence of family history, the differences were still not significant. Our study does not support the contention that the Ser9Gly polymorphism of the DRD3 gene plays a major role in schizophrenia.
Psychiatry Research, 1993
The D, dopamine receptor gene is an important candidate gene for schizophrenia, since-because of its almost exclusive expression in the limbic system-it combines the dopamine receptor hypothesis with the limbic system hypothesis of schizophrenia. Pairwise linkage analyses were carried out between the D, dopamine receptor gene locus (DRD,) and schizophrenia (including major depression among its pleiotropic manifestations). On the basis of these analyses, which assumed a penetrance of 0.71 and a dominant mode of inheritance, we were able to exclude the DRD, locus with a lod score of-2.50 in four Icelandic pedigrees. The area of exclusion (lod score <-2.00) extended 1.2 centimorgans. We conclude that the genetic predisposition to schizophrenia in these pedigrees is not due to a mutation in the DRD, locus. However, these results cannot exclude the possibility that a defect in other genes regulating the expression of the D, dopamine receptor gene could be involved in the pathogenesis of schizophrenia or that linkage analyses in other families or population-based association studies might show a positive result.
There are several lines of evidence implicating the dopamine D3 receptor in the pathophysiology of schizophrenia. The Ser9Gly polymorphism of the dopamine D3 receptor gene (DRD3) has been the most extensively investigated DRD3 variant in connection with the disease but results have been inconclusive. Recent reports indicate that the Ser9Gly polymorphism is in linkage disequilibrium with other markers, but association studies between DRD3 haplotypes and schizophrenia have had mixed results. Genetic heterogeneity may be one of the causes of contradicting results. In order to clarify the role of DRD3 alterations in the aetiology of disease, we have investigated three D3 genetic variants (Ser9Gly, À205-G/A, À7685-G/C) in a sample of patients with schizophrenia or schizoaffective disorder (N=118) and controls (N=162) recruited from a human isolate from Navarra (Northern Spain) of Basque origin. Although no association was found between the Ser9Gly or the À205-A/G polymorphisms and disease, an excess of allele À7685-C was observed in patients ( p=0.002 after correction for multiple analyses). Haplotype analysis shows the three markers to be in strong linkage disequilibrium ( pb0.0001) and strongly associated with disease ( pb1Â10 À5 ). These results may suggest that these polymorphisms exert a combined or synergistic effect on susceptibility to schizophrenia, or are in linkage with an unknown causative factor. However, further replication in independent samples is required. D
Association between schizophrenia and homozygosity at the dopamine D3 receptor gene
Journal of Medical Genetics, 1992
Disturbances in dopamine neurotransmission have been postulated to underlie schizophrenia. We report data from two independent studies of a Ball polymorphism in the dopamine D3 receptor gene in patients with schizophrenia. In both studies, more patients than controls were homozygous (p= 0005, p = 0008). When pooled data were analysed, this difference was highly significant (p = 00001) with a relative risk of schizophrenia in homozygotes of 2-61 (95% confidence intervals 1P60-426).
Neuroscience Letters, 2000
The association between schizophrenia and the Ser9Gly variant of the dopamine D3 receptor gene (DRD3) has been the subject of numerous studies. Under meta-analysis this site, or one or more in linkage disequilibrium with it, appears to contribute a small increase to the relative risk of schizophrenia. In this study, 768 bp of the 5'-leader region of DRD3 mRNA was screened for polymorphisms to assess their contribution to the association of DRD3 with schizophrenia. A cluster of three single nucleotide polymorphisms (SNPs) was identified in tight linkage disequilibrium with each other and with the Ser9Gly polymorphism. One of the 5'-leader SNPs encodes a Lys9Glu variant within a 36 amino acid residue stretch of an upstream open reading frame (uORF). Two common haplotypes are found in the population examined; one is linked to the Ser9 coding variant and the other to the Gly9 variant. A panel of 73 schizophrenic patients and 56 matched controls recruited from the East Anglia region of the United Kingdom was screened for disease association at these sites. Since the 5'-leader and coding sites are in tight disequilibrium, the combined genotype of all 4 sites was scored for each patient. A significant association was seen between disease and the frequency distribution of these genotypes (chi2 = 13.19, d.f. = 3, P = 0.0042; Cochran method for sparse cells applied). A 20% excess of one of the heterozygous genotypes, in which the sequences differ at three of the four SNPs, including Ser9/Gly9 in the receptor and Lys9/Glu9 in the uORF, was found in the patient group. An absence of association of disease with the Ser9Gly polymorphism had previously been reported for this panel. This suggests that these SNPs and the corresponding coding changes may exert a combined or synergistic effect on susceptibility to schizophrenia.
American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 2007
This study aims to further evaluate the controversial association between the Ser9Gly polymorphism in codon 9 of the D3 dopamine receptor gene (DRD3) and schizophrenia in psychiatric inpatients acutely hospitalized in two general hospitals in Madrid, Spain. The Ser9Gly polymorphism of the DRD3 was examined in 178 schizophrenic patients, 286 patients with other psychiatric diagnoses, and 132 controls recruited. Genotype frequencies were in Hardy‐Weinberg equilibrium. No association was found between schizophrenia and the Ser9Gly polymorphism of the D3 dopamine receptor gene. © 2006 Wiley‐Liss, Inc.