A case-control association study of the polymorphism at the promoter region of the DRD4 gene in Korean boys with attention deficit-hyperactivity disorder: evidence of association with the -521 C/T SNP.
Recent genetic studies at the 5' end of the dopamine D4 receptor (DRD4) gene have identified several polymorphisms having a possible relationship with attention deficit-hyperactivity disorder (ADHD). This study examined the association between the -521 and -376 promoter single nucleotide polymorphisms (SNPs) of the DRD4 gene and ADHD through a case-control association study in Korean boys, who constitute a single ethnic population. Ninety-four ADHD and ninety-five control boys were enrolled in this study. All of the ADHD subjects completed a comprehensive and standardized diagnostic and psychological evaluation battery including the ADHD Rating Scale-IV (ARS). Genotyping for the 2 promoter SNPs was performed. There were significant differences in the genotype and allele frequencies of the -521 C/T SNP between the ADHD and control groups (chi2=6.28, p=0.043 and chi2=6.22, p=0.013, respectively). However, the distribution of the -376 C/T genotypes and alleles were similar in the ADHD and control groups. The subtypes of ADHD were not related to either of these two SNPs. In the ADHD subjects, the -521 TT genotype group had a higher score in the inattentive subscale and a lower score in the hyperactive subscale of the parents version of ARS, although these differences did not attain statistical significance (p=0.146, p=0.082). In conclusion, there was a significant association between the -521 C/T SNP and ADHD in Korean boys. These results suggest a role of the -521 C/T SNP in the susceptibility for ADHD.
Yang
Jae-Won
JW
Division of Child & Adolescent Psychiatry, Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Republic of Korea.
Jang
Won-Seok
WS
Hong
Sungdo David
SD
Ji
Yong Ick
YI
Kim
Duk Hwan
DH
Park
Jubae
J
Kim
Swon Woo
SW
Joung
Yoo Sook
YS
D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000235:genetics*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007723:Korea; D008297:Male; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011569:Psychiatric Status Rating Scales; D050638:Receptors, Dopamine D4 / Q000235:genetics*; D018709:Statistics, Nonparametric
C493599:DRD4 protein, human; D050638:Receptors, Dopamine D4