Evaluation of the promoter region polymorphism (5-HTTLPR) in the serotonin transporter gene in females with postpartum depression

The aim of the present study was to investigate the association between polymorphism in the serotonin transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR) in the promoter region of the 5-HTT gene and the pathogenesis of postpartum depression (PPD). Blood samples were collected from 120 female patients with PPD and 140 age-matched normal controls. Polymerase chain reaction analysis was performed to detect the 5-HTTLPR polymorphism in these subjects, and the genotype and allele frequencies were compared between the two groups. The disease severity was evaluated using the Hamilton Depression Rating Scale (HAMD) score. The results showed that the frequency of the homozygous long/long (L/L) genotype was significantly lower in the PPD group than that in the control group; by contrast, the frequencies of the heterozygous long/short (L/S) and homozygous S/S genotypes were similar for the two groups, without significant differences. No significant differences were observed in the L and S allele frequencies between the two groups. Furthermore, compared with the L/S heterozygous and S/S homozygous genotypes, patients with PPD with the L/L homozygous genotype had a significantly lower HAMD score. The present results suggest that female patients with PPD carrying the homozygous L/L genotype may be less susceptible to depressive symptoms and that the L/L genotype may be associated with the reduced occurrence of PPD. These findings provide a theoretical basis for the clinical diagnosis and treatment of PPD.