[Association analysis of dopamine D4 receptor gene polymorphism and attention deficit hyperactivity disorder with/without disruptive behavior disorder].
OBJECTIVE
To examine the role of dopamine D4 receptor gene (DRD4) in attention deficit hyperactivity disorder (ADHD) with/without disruptive behavior disorder (DBD) by focusing on a-521C/T SNP within the promoter region of this gene.


METHODS
A total of 401 DSM-IV ADHD children (including 284 trios) of Chinese Han descent were genotyped. Chi-square test and the transmission disequilibrium test (TDT) were used to test for associations in ADHD with and without DBD respectively.


RESULTS
In the comparison of ADHD with (n=143) and without (n=258) DBD, the -521T allele ( chi(2) = 6.778, P= 0.009, OR= 1.485) and the TT genotype (chi(2) = 6.292,P=0.012,OR=1.729) showed higher frequency in children with ADHD and DBD simultaneously. For family based analysis, T allele of the -521C/T polymorphism was preferentially transmitted to ADHD children with comorbid DBD (n=100, chi(2) = 3.868,P=0.049), whereas no significant distortion was found in the transmission of the tested variant for ADHD without DBD (n=184, chi(2) = 0.223, P=0.637).


CONCLUSIONS
Our findings suggest that the -521C/T SNP of DRD4 may contribute to the predisposition to ADHD with comorbid DBD. This study supports for the hypothesis that ADHD with comorbid DBD may be influenced by greater genetic effect compared to ADHD alone.
Guan
Li-li
LL
Institute of Mental Health, Peking University, Beijing 100083, China.
Wang
Yu-feng
YF
Li
Jun
J
Wang
Bing
B
Yang
Li
L
Qian
Qiu-jin
QJ
D000293:Adolescent; D000483:Alleles; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000235:genetics*; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000453:epidemiology / Q000235:genetics*; D002648:Child; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D020641:Polymorphism, Single Nucleotide; D050638:Receptors, Dopamine D4 / Q000235:genetics*
C493599:DRD4 protein, human; D050638:Receptors, Dopamine D4