Tryptophan Hydroxylase 2 Gene Polymorphism in Anxiety and Depressive Disorder in Kashmiri Population

Abstract

Background: The gene of tryptophan hydroxylase is widely recognized as a major candidate gene in many psychiatric disorders. However, no study has been done which investigates tryptophan hydroxylase 2 gene polymorphism in anxiety and depressive disorders in Kashmiri population (India).Objectives: To study tryptophan hydroxylase 2 (TPH2) C 11993 A gene polymorphism in anxiety and depressive disorders.Method: Sixty patients of depression disorder, 60 patients of anxiety disorder and 40 unrelated healthy volunteers (control) were studied in a case control design. Polymorphism was determined using polymerase chain reaction (PCR) and agarose gel electrophoresis after digestion with HAP II enzyme. Genotypes and allele frequencies were compared using Chi-square tests, Fischer's exact test, odds ratio, 95% confidence interval (C.I) and p-value of <0.05 was considered to be statistical significant. Results:The mean age ± SD of anxiety, depression and control group was 32.73±10.99, 32.20±10 and 29.75±10.12 respectively and the difference was found to be statistically non significant (p=0.349).The mean HAM-A (Hamilton rating scale for anxiety) score and HAM-D (Hamilton rating scale for depression) score was high in both groups (anxiety and depression) and found to be statistically significant (p=0.001).Depression group had AA genotype (55.2%) than control (37.5%) and was found to be statistically non significant (p=0.890).Comparison of allelic frequency revealed no association of A allele in anxiety group (76.67%) compared with control (75.5%) and was found to be statistically non significant (p= 0.866), OR 1.09 (0.56-2.11).Conclusion: TPH2C 11993 A gene was not found to be associated with major depressive disorder (MDD) and anxiety disorder in Kashmiri population.

Is there a link between Depressive Disorders and Tryptophan Hydroxylase 1 (TPH1) Gene Polymorphism? - Study from a Distressed Area, Kashmir (India)

“…Since time immemorial, the valley of Kashmir has been regarded as the paradise on earth because of its splendid natural beauty. Over the last eighteen years, Kashmir valley has seen many downfalls, due to continuous violence, political turmoil, and reign of terror [ 1 , 2 , 15 ]. The last two decades have seen a rise of psychological and psychiatric disorders in Kashmir [ 2 , 3 ].…”

“…Different studies have shown an association of TPH1 gene variants with depressive disorders [ 5 , 7 , 9 ]. Previously, in our earlier study, we found no relationship of another isoform of TPH gene (TPH2) in depressive disorders in Kashmiri (Indian) population [ 1 , 2 ]. As the association of TPH1 gene in depressive disorders in some studies has shown positive association and it was not possible to study all the variants of TPH 1 gene, due to financial and time restraints, TPH1 A779C variant was selected.…”

“…The last two decades in Kashmir (India) have seen around 20,000 deaths and 4,000 disappearances. There have been episodes of continuous violence, political turmoil, and reign of terror, all of which have increased the overall psychiatric morbidity [ 1 - 2 ]. Depression is one of the many psychiatric disorders that can occur due to traumatic events.…”

“…Major depressive disorders (MDD) result from a complex interaction between an individual’s genetic endowment and environmental factors. The influence of environment is difficult to evaluate in a genetic association study and is usually a confounding factor [ 1 , 2 ]. In recent years, attempts to investigate genetic influence for the development of depressive disorders have emerged as one of the prominent areas of neuroscience research [ 4 ].…”

“…In recent years, attempts to investigate genetic influence for the development of depressive disorders have emerged as one of the prominent areas of neuroscience research [ 4 ]. Various candidate genes have been studied for possible association with a major depressive disorder (MDD) [ 1 - 3 ]. Several investigators have pointed out that TPH (Tryptophan hydroxylase) gene may be associated with some psychiatric disorders.…”