Some authors have reported an association of BDNF Val66Met polymorphism with suicidal behavior and/or clinical aspects of suicidal attempts. We evaluated, here, the impact of BDNF Val66Met polymorphism on the clinical characteristics of suicide attempts. The study was conducted on a cohort of 120 consecutive patients who were admitted to the Emergency Hospital of Porto Alegre, Brazil, due to a suicide attempt. Variables of univariate analyses were included in a logistic regression model to test whether the risk factors had independent effect. In univariate analyses, sex, BDNF genotype, intent and method of suicide attempt were all risk factors for high lethality in suicide attempts. After logistic regression analysis, male sex (O.R.=3.03; 95% C.I=1.34-6.84; 0.008) and the presence of BDNF 66Met allele (O.R.=2.62; 95% C.I=1.04-6.57; 0.04) were significantly and independently associated with the high lethality in suicide attempts. The present study showed that BDNF 66Met allele is an independent predictor of high lethality in suicide attempts of depressed patients. This finding is important because it might allow earlier identification of patients at high risk for suicide, perhaps providing better tools for clinical care of these patients in the future.

Different lines of evidence support BDNF as a candidate gene in mood and anxiety modulation. More recently, the Met allele of the BDNF Val66Met polymorphism has been implicated in anxiety in animal models and anxiety-traits in humans. The aim of this study is to evaluate the a priori hypothesis that the association between anxiety disorders and Val66Met polymorphism at the BDNF gene would be replicated in a community sample of children and adolescents. 240 subjects from a total sample of 2457 children and adolescents aged 10-17 years from the public schools in the catchment area of the primary care unit of a university hospital participated in this case-control study and were assessed for psychopathology using the K-SADS-PL. A sample of saliva was collected for DNA analysis of Val66Met polymorphism. BDNF was the single gene evaluated in this sample. We found a significant association between carrying one copy of the Met allele and higher chance of anxiety disorders in children and adolescents. The association remained positive even after the adjustment for potential confounders (228 subjects; OR=3.53 (CI95% 1.77-7.06; p<0.001)). Our results support the a priori hypothesis of an association between anxiety and the polymorphism Val66Met. To our knowledge, this is the first study documenting a potential role of this polymorphism in a community sample of anxious children and adolescents.

INTRODUCTION: Among epileptic patients, those with temporal lobe epilepsy (TLE) are at risk to develop psychiatric disorders. Evidence suggests that the association of psychiatric disorders with epilepsy might be related to common biological substrates. Studies support that serotonin (5-HT) may also contribute to a predisposition to epilepsy. The 5-HTTLPR and 5-HTTVNTR polymorphisms in the 5-HTT gene and the C-1019G polymorphism in the 5-HT1A gene have been studied in psychiatric diseases. As far as we know, this is the first study evaluating a possible genetic involvement in the development of psychiatric comorbidities in epilepsy. OBJECTIVE: It is biologically plausible that alterations in serotonin-related genes may be involved in higher susceptibility to psychiatric disease in the individuals with TLE. Here we report results of an association study of serotonin gene polymorphisms and psychiatry comorbidities in TLE. METHODS: Case-control study of 155 patients with temporal lobe epilepsy. We evaluate the influence of 5-HTTLPR and 5-HTTVNTR polymorphisms in the 5-HTT gene and the C-1019G polymorphism in the 5-HT1A gene in psychiatric comorbidities of TLE. RESULTS: After logistic regression, female sex (O.R.=2.38; 95%CI 1.08 to 5.28; p=0.03) and the presence of C allele of 5-HT1A C-1019G polymorphism (O.R.=2.82; 95% CI 1.02 to 7.81; p=0.04) remained independent risk factors for anxiety disorders in temporal lobe epilepsy (O.R.=2.82; 95% CI 1.02 to 7.81; p=0.04). CONCLUSION: C allele of 5-HT1A C-1019G polymorphism is independent risk factor for anxiety disorders in temporal lobe epilepsy. Other studies will shade some light on molecular mechanisms involved in psychiatric comorbidities in epilepsy. Financiamento: CNPQ e FIPE-HCPA