Association study of the serotonin transporter gene polymorphism in obsessive–compulsive disorder
The hypothesis implicating the serotonergic system in the pathophysiology of obsessive–compulsive disorder (OCD) is supported by the therapeutic efficacy of selective serotonin reuptake inhibitors (SSRIs). Since SSRIs act on the serotonin transporter (5-HTT), it has been suggested that the 5-HTT gene (SCL6A4) could be a good candidate for OCD. The SCL6A4 gene has a 44-bp insertion/deletion polymorphism in its promoter region (5-HTTLPR). Previous studies have revealed an association between OCD and the l allele. We analysed the 5-HTTLPR polymorphic system in 115 Mexican OCD patients and 136 controls. No significant association was found between l allele and OCD (χ2 = 1·54, d.f. = 1, p = 0·21). Furthermore, we assessed alternative methods that employ family-based designs in a sample of 43 trios. Haplotype-based haplotype relative risk and transmission disequilibrium analysis did not show a preferential transmission of l allele to OCD probands. Our results indicate the need to analyse larger samples using family-based methods.(Received October 29 2000)
(Reviewed December 20 2000)
(Revised May 10 2001)
(Accepted May 13 2001)
Key Words: Association study; family-based method; OCD; serotonin transporter gene.
c1 Address for correspondence: H. Nicolini, Departamento de Genética Psiquiátrica, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico D.F., 14370, México. Tel.: (525)573-2437 Fax: (525) 513-3722 E-mail: [email protected]