Association between Tourette syndrome curative effects and the dopamine transporter gene

Abstract

Objective To study the difference of dopamine transporter ( DAT1 )gene 40 bp variable number of tandem repeat ( VNTR ) genotype and allele frequency in TS patients with different curative effect in Chinese Han population. Methods In this study, the 40 bp polymorphism in the DAT1 gene was analyzed by using polymerase chain reaction-variable number of tandem repeat and polymorphism. The clinical data and tic symptoms was assessed with the clinical data schedule table and the Yale Global Tic Severity Scale ( YGTSS ). TS was diagnosed with the Diagnostic and Statistical Manual of Mental Disorders,the Forth Edition( DSM-Ⅳ )diagnostic criteria for Tourette syndrome. Results There was no significant differences in the frequencies of genotype for DAT1 gene 40 bp VNTR between normal controls ( 57 samples )and common TS children ( 52 samples ) and refractory TS children ( 63 samples ) (χ2 = 12. 638, P =0.125).The allele 440bp tended to be more in children with refractory TS(refractory TS:commmon TS:normal controls=8:1:0),but with no significat differences(χ2=11.352,P=0.053).Conclusions The DAT1 gene 40 bp VNTR 440 bp allele frequency seems to be higher in children with refractory TS,which suggests common TS and refractory TS have different genetic background. It should be verified by making larger samples in future study. Key words: Tourette syndrome; Dopamine plasma membrane transport proteins; Genotype; Treatment outcome