No evidence for an association between the BDNF Val66Met polymorphism and schizophrenia or personality traits

Brain-derived neurotrophic factor (BDNF) is a member of the nerve growth factor family, which plays a critical role in neurodevelopment. Based on the neurodevelopmental hypothesis, the BDNF gene has been a candidate locus for schizophrenia. In Caucasians, recent studies identified an association with the Val66Met polymorphism, which has been suggested to affect episodic memory and hippocampal function in humans. However, in other populations, the association has not been replicated. In the present study, we investigated the association between the Val66Met polymorphism of the gene and schizophrenia in 401 Japanese patients with schizophrenia and 569 controls. As a result, we did not observe a significant difference in genotypic distribution or allele frequencies between the patients and controls (chi2=0.56, df=2, p=0.76 and chi2=0.39, df=1, p=0.53, respectively). We also investigated the association between the polymorphism and personality traits in the controls; however, no significant association was observed. Thus, the present study did not provide evidence for an association between the BDNF gene and schizophrenia or personality traits in the Japanese population.