The Association between Brain-Derived Neurotrophic Factor Gene Polymorphisms and Suicidal Behavior in Major Depression

Objectives: Previous studies have suggested that genetic factors affect suicidal behavior in major depression. In particular, Brain-Derived Neurotrophic Factor (BDNF) genes have received much attention because of a possible association between such genes and suicidal behavior in major depression. In this study, we aimed to investigate associations between two BDNFSNPs (196G/A, 11757G/C) and suicidal behavior in major depression. Method: Participants were 120 Major Depressive Disorder (MDD) patients attempting suicidal behavior, 117 non-suicidal MDD patients and 180 healthy controls. The genotype and allele frequencies of each group were analyzed using chi-squared statistics. Frequencies and haplotype reconstructions were calculated using SNP Analyzer 2.0. Results: No significant associations were found between genotype distributions or allele frequencies of the two tested polymorphisms (196 G/A, 11757G/C) among suicidal MDD patients, non-suicidal MDD patients and controls. In the haplotype study, there was also no significant difference in haplotype analysis between suicidal MDD patients and non-suicidal MDD patients. However, the BDNF 196A?11757C haplotype combinations and196G? 11757C haplotype combination were significantly lower in the suicidal MDD group and non-suicidal MDD group compared to healthy controls. Conclusion: We did not find any relation between the tested BDNF genes and suicidal behavior in MDD. However, this study is significant in that this is the first haplotype study that tried to identify the associations between BDNF SNPs and suicidal behavior in a Korean population. Future research should be conducted with larger sample size sand more genetic markers, taking ethnicity into consideration.