No association between catechol-o-methyltransferase Val108/158Met polymorphism and schizophrenia or its clinical symptomatology in a Mexican population.

The gene coding for catecol-o-methyltransferase (COMT), participant in the metabolism of catecholamines, has long been implicated as a candidate gene for schizophrenia. We determined the relation of the COMT Val108/158Met polymorphism with schizophrenia or its symptomatology (negative, disorganized and psychotic dimension). We conducted a case-control study comprising 186 patients with schizophrenia and 247 controls. The diagnosis of schizophrenia was established using the DSM-IV criteria for this illness. The clinical symptomatology was assessed through the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. No significant differences were found in the distribution of alleles (χ2 = 0.01, df = 1, p = 0.90) or genotypes (χ2 = 1.66, df = 2, p = 0.43) between schizophrenic patients and the control group. Multivariate analysis showed that the COMT Val108/158Met polymorphism has no influence in the clinical symptomatology of schizophrenia. Our results showed no association between COMT Val108/158Met and schizophrenia or evidence for an association between COMT and the clinical symptomatology of this illness. This suggests that the COMT gene may not contribute to the risk for schizophrenia among the Mexican population.

No association between the HTR1A gene and suicidal behavior: a meta-analysis.

OBJECTIVE: Dysfunction of serotonin 1A receptors (HTR1A) may play a role in the genesis of suicidal behavior. We studied the association between a functional polymorphism in the HTR1A gene and suicidal behavior. METHOD: We performed a meta-analysis of published genetic association studies by searching through Medline, PubMed, and Web of Science databases to analyze a possible correlation between the rs6295 polymorphism and suicidal behavior in different populations. RESULTS: Four studies comprising a total of nine hundred and fifty seven patients with suicidal behavior and nine hundred and fifty seven controls were the eligible. The G allele of the rs6295 polymorphism may not be associated with suicidal behavior (Random-effects model: OR = 1.08; 95% CI: 0.80-1.45; p(Z) = 0.80) in presence of heterogeneity (Q = 17.84, df = 4, p = 0.0013). In a second analysis that presented no heterogeneity, a negative association was also observed (OR = 0.94; 95%CI: 0.79-1.13; p(Z) = 0.99). CONCLUSION: To our knowledge, the present study is the first meta-analysis searching for a correlation between rs6295 of HTR1A and suicidal behavior. Our results showed no association between HTR1A and suicidal behavior. However, more studies assessing different populations, as well as larger samples, are needed.

No association between the HTR1A gene and suicidal behavior: a meta-analysis / A não associação entre o gene HTR1A e comportamento suicida: uma metanálise

OBJECTIVE: Dysfunction of serotonin 1A receptors (HTR1A) may play a role in the genesis of suicidal behavior. We studied the association between a functional polymorphism in the HTR1A gene and suicidal behavior. METHOD: We performed a meta-analysis of published genetic association studies by searching through Medline, PubMed, and Web of Science databases to analyze a possible correlation between the rs6295 polymorphism and suicidal behavior in different populations. RESULTS: Four studies comprising a total of nine hundred and fifty seven patients with suicidal behavior and nine hundred and fifty seven controls were the eligible. The G allele of the rs6295 polymorphism may not be associated with suicidal behavior (Random-effects model: OR = 1.08; 95 percent CI: 0.80-1.45; p(Z) = 0.80) in presence of heterogeneity (Q = 17.84, df = 4, p = 0.0013). In a second analysis that presented no heterogeneity, a negative association was also observed (OR = 0.94; 95 percentCI: 0.79-1.13; p(Z) = 0.99). CONCLUSION: To our knowledge, the present study is the first meta-analysis searching for a correlation between rs6295 of HTR1A and suicidal behavior. Our results showed no association between HTR1A and suicidal behavior. However, more studies assessing different populations, as well as larger samples, are needed.

OBJETIVO: É possível que uma disfunção nos receptores 1A de serotonina (HTR1A) desempenhe um papel na origem do comportamento suicida. Estudamos a associação entre um polimorfismo funcional no gene HTR1A e comportamento suicida. MÉTODO: Realizamos uma metanálise de estudos de associação genética já publicados através de uma busca nos banco de dados do Medline, PubMed e Web of Science para identificar uma possível correlação entre o polimorfismo rs6295 e comportamento suicida em diferentes populações. RESULTADOS: Foram selecionados quatro estudos com um total de 957 pacientes com comportamento suicida e 957 controles. O alelo G do polimorfismo rs6295 não pôde ser associado a comportamento suicida (modelo de efeitos aleatórios: OR = 1,08; 95 por centoCI: 0,80-1,45; p(Z) = 0,80) na presença de heterogeneidade (Q = 17,84, df = 4, p = 0,0013). Em uma segunda análise, sem heterogeneidade, também foi observada uma associação negativa (OR = 0,94; 95 por centoCI: 0,79-1,13; p(Z) = 0,99). CONCLUSÃO: Pelo que nos consta, trata-se da primeira metanálise cujo objetivo é identificar uma correlação entre o polimorfismo rs6295 do HTR1A e comportamento suicida. Os nossos resultados não demonstraram existir uma correlação entre o HTR1A e comportamento suicida. No entanto, são necessários estudos adicionais que incluam outras populações, assim como amostras maiores.

No association between COMT val158met polymorphism and suicidal behavior: meta-analysis and new data.

BACKGROUND: The polymorphism COMTval158met has been associated with suicidal behavior in case-control and meta-analysis studies, but results and conclusions remain controversial. The objective of this study was to examine the association between COMT val158met with suicidal behavior in a case-control study and to assess the combined evidence -this case-control study and available data from other related studies- we carried out a meta-analysis. METHODS: We conducted a case-control study with 105 patients with suicide attempts and 236 controls. Subsequently, we performed a meta-analysis of published genetic association studies by searching through Medline, PubMed and Web of Science databases. RESULTS: No significant differences were found in the distribution of alleles (χ2 = 0.33, 1 df, p = 0.56) or genotypes (χ2 = 2.36, 2 df, p = 0.26). The meta-analysis comprising 12 association studies (including the present one) showed that the risk COMTmet allele of COMTval158/met is not associated with suicidal behavior (OR: 1.09, 95% CI: 0.97-1.23), even in the absence of heterogeneity (OR: 1.09, 95% CI: 0.97-1.23). CONCLUSION: Our results showed no association between COMTval158/met and suicidal behavior. However, more studies are necessary to determine conclusively an association between COMT and suicidal behavior.

APOE-epsilon3 and APOE-219G haplotypes increase the risk for schizophrenia in sibling pairs.

To investigate the role of the apolipoprotein E (APOE) gene in schizophrenia, the authors analyzed 60 families with this mental disorder. An association in the presence of linkage test (APL) and haplotypes analysis were undertaken using the APL v1.1 software. A global allelic transmitted was significant for APOE-epsilon3 (chi(2)=6.24, p=0.01); this allele is mainly carried by female patients (chi(2)=8.33, p=0.003), whereas APOE-219G is preferentially transmitted in males (p=0.02). Furthermore, our results show that haplotypes APOE-epsilon3/APOE-219G are associated with schizophrenia (chi(2)=11.61, p=0.01). These results provide evidence that the APOE gene may play a significant role in the etiology of schizophrenia in the Mexican population.