No implication of brain-derived neurotrophic factor (BDNF) gene in unipolar affective disorder: evidence from Belgian first and replication patient-control studies.

Several lines of evidence have suggested an implication of brain-derived neurotrophic factor (BDNF) in unipolar affective disorder (UPAD). In the present study, we investigated the role of BDNF gene in UPAD in two independent samples of 92 patients/92 controls and 156 patients/197 controls. Two single nucleotide polymorphisms (SNPs) were investigated. We found no significant differences of BDNF gene SNPs distribution between UPAD patients and controls in both samples. Haplotype analyses were performed on both samples. A statistical difference was found between cases and controls in the first sample but not in the second. These results are not in favour of an implication of BDNF in UPAD but need to be replicated before final conclusion.