["Overlaps in clinical, pathological and molecular characteristics of Parkinson's disease (PD) and Major Depressive Disorder (MD-D) have promoted association studies in search of common genetic risk factors that may predispose or modify this spectrum of disorders. Experimental and clinical data suggest that genetic variations in Brain-derived neurotrophic factor (BDNF) gene may increase the risk for PD and MD-D.", 'Two hundred and sixty-six PD, 83 MD-D and 400 controls were recruited for this study, assessed using a battery of neuropsychological tests, and genotyped for 11757C/G, 712A/G, 196A/G, and 270C/T in BDNF gene.', '712A/G was associated with 2.50-fold time risk of PD. By combining genotypes AG/AA with 712 GG genotype as reference (OR=1) in stratification analysis, AG/AA genotypes were associated with PD (OR=2.94, 95% CI=1.88-4.61). Accordingly, the A allele was significantly overrepresented in PD compared with the G allele (OR=3.16, 95% CI=2.08-4.81). This distribution in females and males were similar.'] Is the 712A/G polymorphism of Brain-derived neurotrophic factor associated with Parkinson 's disease but not Major Depressive Disorder in a Chinese Han population?