Oxytocin receptor gene single nucleotide polymorphisms in patients with bipolar disorder.

Introduction: Many studies have reported that psychiatric disorders may be associated with oxytocin receptor (OXTR) gene polymorphisms. The aim of this study was to investigate whether there is a relationship between OXTR gene polymorphisms and bipolar disorder (BPD).

Methods: The study included 100 patients diagnosed with BPD type 1 (BPD I) and 96 healthy controls. Single nucleotide polymorphisms (SNPs) of the OXTR gene, including rs53576, rs2254298 and rs2268494, were examined via polymerase chain reaction in blood samples taken from the study participants. Based on the BPD determinants, the patients were divided into 4 subgroups, as those with psychotic features, seasonal patterns, rapid cycling and peripartum onset.

Results: The frequency of the rs2268494 A allele was lower in the patients than in the healthy controls (p = .048), that frequency of psychotic mania was higher in patients with the rs53576 GG genotype compared to the A allele carriers (p = .003), and that of the seasonal pattern was higher in those carrying the rs2268494 A allele compared to those carrying the rs2268494 TT genotype (p < .001).

Conclusion: OXTR gene polymorphisms may be associated with several clinical determinants of BPD. Multicentre studies involving more subjects are required to verify these findings.