Association between the polymorphism in the promoter region of dopamine D4 receptor gene and chronic tic disorder / 中国当代儿科杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study a possible association between the three functional polymorphisms in the promoter region of dopamine D4 receptor (DRD4) gene and chronic tic disorder.</p><p><b>METHODS</b>Genomic DNA was isolated from the venous blood leukocytes of 84 unrelated patients with chronic tic disorder (Study group) and 100 healthy unrelated individuals (Control group). Polymorphisms of DRD4, 1240L/S, 616C/G and 521C/T, were genotyped by the allele-specific primer (ASP) PCR. Genotype, allele and haplotype frequencies were analysed by SHEsis online.</p><p><b>RESULTS</b>There were significant differences in both allele and genotype frequencies (chi(2) = 8.419, P < 0.01; chi(2) = 7.860, P < 0.05 respectively) of DRD4-616C/G between the Study and the Control groups. Haplotypic frequencies of LCT (1240L/S, 616C/G, 521C/T) in the Study group were noticeably higher than in the Control group (chi(2) = 6.371, P < 0.05).</p><p><b>CONCLUSIONS</b>There is an association between the DRD4-616C/G polymorphism and chronic tic disorder. The individuals with haplotype LCT (1240L/S, 616C/G, 521C/T) are susceptible to this disorder.</p>