Association of catechol-O-methyl transferase (COMT) gene -287A/G polymorphism with susceptibility to obsessive-compulsive disorder in Chinese Han population

Several studies suggested a genetic component in the etiology of obsessive-compulsive disorder (OCD). COMT involves in the degradation of dopamine and norepinephrin. As another functional SNP locus, COMT -287A/G polymorphism showed an effect on enzyme activity, suggesting that it may influence brain dopamine levels. To identify association of COMT -287A/G polymorphism with susceptibility to OCD in Chinese Han population. We evaluate the genetic contribution of the COMT -287A/G polymorphism in 200 OCD patients and 403 OCD-free control of Chinese Han population by PCR-RFLP. In addition, we investigate whether COMT -287A/G polymorphism is associated with one or more of these symptom dimensions or other characteristics such as sex, age of onset, and tic-relatedness and evaluate the association of the factorial structure of OCD symptoms from the Y-BOCS checklist with the COMT -287A/G polymorphism. A statistical difference was found in the genotypic frequencies of COMT -287A/G between the OCD and control groups (χ(2) = 13.99, DF = 2, P = 0.00091) and in the genotypic frequencies of GG genotype versus AA and AG genotypes of COMT -287 (χ(2) = 13.49, DF = 1, P = 0.00024, OR = 3.43, 95% CI = 1.78-6.62). There was a trend for an association in the genotypic distributions of COMT -287A/G polymorphism of males (χ(2) = 27.81; DF = 2; P < 0.001) and females (χ(2) = 7.31; DF = 2; P = 0.026) between the OCD patients and the controls. Using principal component analysis, we derived 5 factors from 12 main contents of OCD symptoms from the Y-BOCS checklist and found no association with COMT -287A/G polymorphism. Our study supports the involvement of the COMT -287A/G polymorphism in the genetic susceptibility to OCD in Chinese Han population.