This study was conducted to explore the possibility of association between the single-nucleotide polymorphisms rs6264 of BDNF, rs5443 of GNB3, and rs1801133 of MTHFR; the In/Del polymorphism of ACE; and the ε2 allele of APOE and major depressive disorder (MDD) and recurrent depressive disorder (RDD) in an East Slavic population. | Genetic analysis of BDNF, GNB3, MTHFR, ACE and APOE variants in major and recurrent depressive disorders in Russia