RESUMO
A defect in the dopamine system has been hypothesized as the etiological defect in Gilles de la Tourette syndrome (TS). In this report, we test the hypothesis that the dopamine D5 receptor locus (DRD5) is linked to the genetic susceptibility to TS in five families studied in Canada. We tested for linkage to the dopamine D5 receptor gene using a microsatellite polymorphism located in the same cosmid clone. Using an autosomal dominant model with reduced penetrance, we were able to exclude linkage in four of the five families for the TS and chronic multiple tics (CMT) phenotype. Also, no evidence for linkage was found using nonparametric methods in all five families.
Assuntos
Ligação Genética , Receptores de Dopamina D1/genética , Síndrome de Tourette/genética , Canadá , Feminino , Genes Dominantes , Genótipo , Humanos , Escore Lod , Masculino , Repetições de Microssatélites , Linhagem , Fenótipo , Polimorfismo Genético , Receptores de Dopamina D5 , Software , Transtornos de Tique/genética , Transtornos de Tique/metabolismo , Síndrome de Tourette/metabolismoRESUMO
Gilles de la Tourette Syndrome (TS) is neuropsychiatric disorder characterized by both motor and vocal tics affecting approximately 1/10,000 females and 1/2000 males. Because of the success of neuroleptics and other agents interacting with the dopaminergic system in the suppression of tics, a defect in the dopamine system has been hypothesized in the etiology of TS. In this paper we test the hypothesis that the dopamine D4 receptor (DRD4) is linked to the genetic susceptibility to TS in five families. We tested three polymorphisms in the DRD4 gene and a polymorphism in the closely linked locus, tyrosine hydroxylase (TH). We found no evidence for linkage of DRD4 or TH to TS using an autosomal dominant model with reduced penetrance or using non-parametric methods. The presence of a mutation that results in a truncated non-functional D4 receptor protein was also tested for, but was not observed in these families.