Transmission disequilibrium test of DRD4 exon III 48bp variant number tandem repeat polymorphism and tic disorder.
- Author:
Yi HUANG
1
;
Xiehe LIU
;
Tao LI
;
Lanting GUO
;
Xiaohong MA
;
Guanggu YUAN
;
Rong PENG
Author Information
- Publication Type:Journal Article
- MeSH: Adolescent; Adult; Alleles; Attention Deficit Disorder with Hyperactivity; complications; genetics; Child; Child, Preschool; DNA; genetics; Exons; genetics; Family Health; Female; Gene Frequency; Genotype; Humans; Linkage Disequilibrium; Male; Minisatellite Repeats; genetics; Polymorphism, Genetic; Receptors, Dopamine D2; genetics; Receptors, Dopamine D4; Tic Disorders; complications; genetics
- From: Chinese Journal of Medical Genetics 2002;19(2):100-103
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo investigate whether DRD4 exon III48 bp variant number tandem repeat(VNTR) polymorphism is associated with tic disorder.
METHODSOne hundred and twenty-two nucleus families were collected using Structured clinical interview for genetic study of Tourette syndrome and related disorders for family-based association analysis of tic disorder and DRD4 exon III 48bp VNTR polymorphism. One hundred and twenty-two trios were divided into two groups: tic disorder group (82 trios of Tourette syndrome or chronic tic disorder, TS&CT) and tic disorder accompanied with attention deficit and hyperactivity disorder (ADHD) group (40 trios of Tourette syndrome or chronic tic disorder accompanied with ADHD, TS&ADHD). Transmission disequilibrium test (TDT), in addition to polymerase chain reaction and VNTR technique were conducted in 122 trios.
RESULTSThere exist 5 alleles at this polymorphic locus in this sample including DRD4 exon III 48bp 2-6 repeats. No transmission disequilibrium was found between DRD4 exon III 48 bp VNTR and tic disorder (chi square=7.44, P 0.12); however, when the sample was divided into two groups, transmission disequilibrium was noticed between the cases of TS&ADHD and this locus by overall allele-wise analysis (chi square=11.74, P 0.02), and there exists transmission disequilibrium exclusively between 5 or 6 repeats of 48bp VNTR(longer alleles) by allele-wise analysis (chi square=10.57, P 0.032, chi square=6.13, P 0.01). No transmission disequilibrium was seen between TS&CT and DRD4 exon III 48bp VNTR(chi square=3.38, P 0.50).
CONCLUSIONThe results of this study have revealed an association between the longer alleles of DRD4 exon III 48bp VNTR polymorphism and tic disorder accompanied with ADHD, thus suggesting a possible genetic risk factor of tic disorder accompanied with ADHD in Chinese.
