The G-712A polymorphism of brain-derived neurotrophic factor is associated with major depression but not schizophrenia.

Brain-derived neurotrophic factor (BDNF) is needed to support neuronal survival and differentiation. It also promotes synaptic remodeling and modulates the function of many other neurotransmitters. BDNF is implicated in major depression (MD), and to a lesser extent, in schizophrenia. In the current study, we examined BDNF polymorphisms (G-712A, C270T and Val66Met) in 202 patients with MD and 323 patients with schizophrenia. Results were compared to 346 healthy individuals. The analysis revealed a strong association between the G-712A genotype distribution and MD (p=0.0005). The frequency of the -712A allele was significantly higher in MD patients than in the healthy controls (p=0.0007). The -712AG heterozygote was associated with higher Hamilton score in MD patients. No association was found between schizophrenia and the three BDNF variants. These findings support an important role of G-712A polymorphism of BDNF in MD, and may guide future studies to identify genetic risk factors for MD.