brain-derived neurotrophic factor val66met polymorphism and its synergism with l/s polymorphism in the promoter region of serotonin transporter in bipolar i disorder patients in western iran

Background: brain-derived neurotrophic factor (bdnf) might involve in the pathogenesis of mental disorders. there are inconsistent reports related to the role of bdnf val66met in susceptibility to bipolar disorder (bd). objectives: the aim of the present study was to investigate the role of bdnf val66met and its synergism with 5-htt gene-linked polymorphic region (5-httlpr) variants in susceptibility to bipolar i disorder (bp-i) in western iran. materials and methods: in this case-control study, 153 patients with bp-i and 146 age- and gender-matched healthy individuals were investigated for bdnf and 5-httlpr variants using pcr-rflp method. results: the frequency of bdnf a (met) allele in patients (17.7%) was slightly lower than that in controls (19.9%, p = 0.5). the concomitant presence of bdnf g (val) and 5-httlpr s alleles tended to increase the risk of bp-i by 1.41 times (p = 0.064) compared to the combined presence of bdnf g and 5-httlpr l alleles. also, interaction between bdnf g (val) and 5-httlpr s tended to increase the risk of bp-i by 1.28-fold (p = 0.062) compared to the concomitant presence of bdnf a and 5-httlpr s alleles. conclusions: this study, conducted for the first time on kurdish population in western iran, did not indicate any association be- tween bdnf val66met with bp-i. however, the interaction between bdnf and 5-httlpr variants tended to increase the susceptibility to bp-i.