Association of Catechol-O-methyltransferase val/met polymorphism with cognitive function in Gilles de la Tourette syndrome patients.

Gilles de la Tourette syndrome (GTS) is a kind of neuropsychiatric disorder with childhood onset. The cognitive dysfunction caused by GTS could affect the growth and learning of children and adolescents. The mechanism of cognitive functions was associated with dopaminergic system, thus we access the associations between polymorphism of some dopaminergic system-related genes including Catechol-O-methyltransferase (COMT) met/val, Dopamine receptor D4 (DRD4) exon III 48 bp VNTR (variable number of tandem repeats), Interleukin 1 (IL-1) Ra 86 bp and IL-1β exon 5, and cognitive functions in GTS patients. Genotyping analysis was performed through polymerase chain reaction (PCR). Test for cognitive functions of GTS patients included modified wisconsin card sorting test (WCST), trail making test, visual reproduction test, stroop test and verbal fluency test. The patients with COMT met/met genotype showed less perseverative errors in modified WCST test compared with patients with COMT val/val genotype (P < 0.05). Meanwhile, patients without allele val had better delayed memory in visual reproduction test, less errors in the stroop test and less perseverative errors in modified WCST test compared with patients with allele val (P < 0.05). However, no significant difference was found in cognitive functions among patients with different genotypes or alleles of polymorphisms of DRD4 exon III 48 bp VNTR, IL-1 Ra 86 bp and IL-1β exon 5 (P > 0.05). Polymorphism of COMT met/val was correlated with cognitive functions in GTS patients. This study provided basis for the analysis of molecular genetic pathology of cognitive dysfunctions in GTS.