A multi-factorial illness that causes morbidity threatens life and affects the quality of life is the major depressive disorder (MDD). Serotonergic dysfunction is one of the most described theories of psychiatric symptoms. Several serotonergic genes have been reported in associated with MDD. Recent studies have suggested that serotonin transporter length polymorphic region (5HTTLPR), Tryptophan hydroxylase gene 1 (TPH1) and Tryptophan hydroxylase gene 2 (TPH2) are associated with MDD. In the present study, we have examined the possible correlation between serotonergic genes 5HTTLPR, TPH1 (A218C), and TPH2 (G703T) polymorphism in MDD patients in Coimbatore tertiary care hospital. Blood samples were collected from 245 major depressive disorder patients and 250 healthy volunteers belonging to the faculty of Karpagam College of Medical Science and Research. All the samples were analysed by PCR-RFLP method. The chi-square test has been used for comparing genotype and allele distribution of cases and controls. We observed the 5HTTLPR L/S genotype and allele frequencies (P=0.001and p= 0.001) and TPH2 (G703T) (P=0.0002 and P= 0.005) TPH1 (A218C) (P=0.48 and P=0.43) polymorphisms with MDD. We also observed higher homozygous genotype frequencies of the short allele of 5HTTLPR, the G allele of TPH2 G703T polymorphism in patients. In short, our preliminary study suggests that the 5HTTLPR L/S and TPH2 G703T gene polymorphism were associated with the MDD. Serotonergic genes polymorphism in MDD patients and control groups were compared. Further clinical trials are to be carried out to find the exact mechanisms of the serotonergic system in MDD.
An evaluation of the association of serotonergic genes in patients with major depressive disorders in a tertiary care hospital in Coimbatore
