The Val66Met polymorphism of the brain-derived neurotrophic-factor gene is associated with geriatric depression

Brain-derived neurotrophic-factor (BDNF), the most abundant of the neurotrophins in the brain, has been implicated in both major depression and cognitive function. This study examines the association between the BDNF-gene Val66Met polymorphism and depression susceptibility and severity, age-of-onset, cognitive function and suicidal attempt history in an elderly Chinese sample population. We genotyped the BDNF-gene Val66Met polymorphism in 110 elderly inpatients diagnosed with major depression and 171 age- and sex-similar control subjects. All patients were assessed with the Hamilton Rating Scale for Depression (HAM-D) for depression severity and the Mini-Mental Status Examination (MMSE) for cognitive function after admission. Suicide attempt history and age-of-onset of depression were evaluated by interview and medical record. The BDNF Val66Met genotype distribution was significantly different between depressed patients and control subjects (P = 0.003) and there was a significant excess of Met allele in the depressed patients compared to the control group (P = 0.001). The BDNF polymorphism did not affect age-of-onset, depression severity, cognitive function or suicidal attempt history. The results suggest that the BDNF Val66Met polymorphism is a relevant risk factor for geriatric depression.