INCREASED PREVALENCE OF THE 7-REPEAT VARIANT OF THE DOPAMINE D4 RECEPTOR GENE IN PATIENTS WITH OBSESSIVE-COMPULSIVE DISORDER WITH TICS

The polymorphism characterized by a varying number of 48 bp repeats (V NTR) in the dopamine D4 receptor (DRD4) gene was examined in 61 obsess ive-compulsive disorder (OCD) probands with and without ties. Most of the OCD patients with ties showed at least one copy of the 7-fold vari ant compared to those affected subjects without ties (91 vs. 48%, resp ectively, Yates corrected chi(2) = 5.54, P = 0.018), Similarly, a high er number of copies of this common variant were detected in the group of probands displaying ties compared to those OCD's without ties (Yate s corrected chi(2) = 4.66, P = 0.03). Our study suggests that the seve n-repeat allele of the DRD4 gene could be a factor in the phenotypic v ariance of ties among OCD individuals. (C) 1997 Elsevier Science Irela nd Ltd.