Abstract
OBJECTIVE: Brain-derived neurotrophic factor (BDNF) plays an important role in the survival, differentiation, and outgrowth of select peripheral and central neurons throughout adulthood. Growing evidence suggests that BDNF is involved in the pathophysiology of mood disorders. METHODS: Ten single nucleotide polymorphisms (SNPs) across the BDNF gene were genotyped in a sample of 1749 Caucasian Americans from 250 multiplex bipolar families. Family-based association analysis was used with three hierarchical bipolar disorder models to test for an association between SNPs in BDNF and the risk of bipolar disorder. In addition, an exploratory analysis was performed to test for an association of the SNPs in BDNF and the phenotypes of rapid cycling and episode frequency. RESULTS: Evidence of association (P<0.05) was found with several of the SNPs using multiple models of bipolar disorder; one of these SNPs also showed evidence of association (P<0.05) with rapid cycling. CONCLUSION: These results provide further evidence that variation in BDNF affects the risk for bipolar disorder.