Association study between obsessive-compulsive disorder and serotonergic candidate genes.

Abstract Background To date, research examining the relationship between serotonergic genes and obsessive–compulsive disorder (OCD) has yielded conflicting results. The purpose of this study is to investigate the association between four serotonergic polymorphisms (STin2 VNTR and 5-HTTLPR of the SLC6A4 gene, and A-1438G (rs6311) and T102C (rs6313) of the HTR2A gene) and OCD. Methods 99 OCD patients, 456 non-OCD psychiatric patients, and 420 healthy controls from a homogeneous Spanish Caucasian population were genotyped using standard methods. Results All groups showed Hardy–Weinberg equilibrium for the analyzed genetic variability. A-1438G and T102C polymorphisms were in complete linkage disequilibrium. OCD patients showed an excess of STin2.12 carriers (12/12, 12/10, and 12/9 genotypes) compared with healthy controls ( χ 2 (1) = 7.21, corrected p  = 0.021; OR = 3.38, 95% CI = 1.32–8.62) and non-OCD psychiatric patients ( χ 2 (1) = 6.70, corrected p  = 0.030; OR = 3.24, 95% CI = 1.27–8.26). However, no differences were found between non-OCD patients and healthy controls ( χ 2 (1) = 0.05, corrected p > 1; OR = 1.04, 95% CI = 0.72–1.51). No significant differences were found with respect to A-1438G and 5-HTTLPR polymorphisms. Conclusions Our data provide supporting evidence of an association between the STin2 VNTR polymorphism of the SLC6A4 gene and OCD.