Association Between Tryptophan Hydroxylase-2 Gene and Late-Onset Depression

Abstract

The aim of this study was to examine the association between polymorphisms (SNP) in the tryptophan hydroxylase-2 (TPH2) gene and late-onset depression (LOD) in the Brazilian population. We genotyped 8 tag SNPs in the TPH2 gene in 84 outpatients with LOD and 79 individuals belonging to the comparison group to investigate an association between the TPH2 gene and LOD. Our findings suggested an association between tag SNP rs4565946 heterozygous C/T (p = 0.034; χ2 = 6.7; df = 2) and decreased risk of LOD. The tag SNP rs11179000 ancestral homozygous A/A (p = 0.025; χ2 = 7.3; df = 2) and increase risk of LOD and allelic association of ancestral allele A and increase risk of LOD was demonstrated (p = 0.005; χ2 = 7.8; df = 1). We found the statistically significant association between two tag SNPs and LOD. Our results support the hypothesis that the TPH2 gene is associated with LOD.