Cruz C, Camarena B, King N, Páez F, Sidenberg D, de la Fuente J R, Nicolini H
Departamento de Genética Psiquiátrica, Instituto Mexicano de Psiquiatría Calzada Mexico-Xochimilco, San Lorenzo Huipulco, Mexico D.F.
Neurosci Lett. 1997 Aug 1;231(1):1-4. doi: 10.1016/s0304-3940(97)00523-5.
The polymorphism characterized by a varying number of 48 bp repeats (VNTR) in the dopamine D4 receptor (DRD4) gene was examined in 61 obsessive-compulsive disorder (OCD) probands with and without tics. Most of the OCD patients with tics showed at least one copy of the 7-fold variant compared to those affected subjects without tics (91 vs. 48%, respectively, Yates corrected chi2 = 5.54, P = 0.018). Similarly, a higher number of copies of this common variant were detected in the group of probands displaying tics compared to those OCD's without tics (Yates corrected chi2 = 4.66, P = 0.03). Our study suggests that the seven-repeat allele of the DRD4 gene could be a factor in the phenotypic variance of tics among OCD individuals.
