title: Association between the polymorphism in the promoter region of dopamine D4 receptor gene and chronic tic disorder.
abstract: OBJECTIVE
  To study a possible association between the three functional polymorphisms in the promoter region of dopamine D4 receptor (DRD4) gene and chronic tic disorder.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Center of Medical Laboratory Technology, China Medical University, Shenyang, Liaoning 110001, China. luyaosy@hotmail.com
authors.forename: Yao
authors.initials: Y
authors.lastname: Lu
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Ma
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Xi
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Lu
authors.initials: L
authors.lastname: Yao
authors.forename: Jian
authors.initials: J
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Mo
authors.initials: M
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D002648:Child; D002908:Chronic Disease; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D050638:Receptors, Dopamine D4 / Q000235:genetics*; D013981:Tic Disorders / Q000235:genetics*
chemical_list: D050638:Receptors, Dopamine D4