ADHDgene Database

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Large-scale studies

Data Summary

Published Variant
- SNP: 1391
- CNV: 398
- Others: 173
Published Gene: 359
Published Region: 128
Pathway by PBA: 8
Study: 361

Study Report

Basic Info

Reference	Brookes KJ, 2005 (a)16143039
Citation	Brookes K. J., Xu X., Chen C. K., Huang Y. S., Wu Y. Y. and Asherson P. (2005) "No evidence for the association of DRD4 with ADHD in a Taiwanese population within-family study." BMC Med Genet, 6: 31.
Study Design	family-based
Study Type	Candidate-gene association study
Sample Size	216 ADHD probands and available parents
Predominant Ethnicity	Mongoloid
Population	China
Gender	192 (83.6%) were males
Age Group	Children/Adolescents : 5-15 years

Detail Info

Summary	Here they investigated two markers within the DRD4 gene in a Taiwanese population, the exon 3 variable number tandem repeat (VNTR) and a 5' 120 base-pair duplication. Within-family transmission disequilibrium tests of association of the 5' 120 base-pair duplication, and exon 3 VNTR in a Taiwanese population. No evidence of association of ADHD with either polymorphism in this population was observed. The DRD4 gene markers investigated were not found to be associated with ADHD in this Taiwanese sample.
Total Sample	216 ADHD probands between the ages of 5-15 years and available parents were recruited into the study from the Child Psychiatric Clinics in the Chang Gung Memorial Hospital in Taipei area, Taiwan. A total of 192 (83.6%) were males.
Sample Collection	216 ADHD probands between the ages of 5-15 years and available parents were recruited into the study from the Child Psychiatric Clinics in the Chang Gung Memorial Hospital in Taipei area, Taiwan.
Diagnosis Description	The diagnosis of ADHD was made according to DSM-IV criteria following completion of a standard maternal interview (Kiddie-SADS) and completion of parent and teacher Conner's revised rating scales. In all 78% had the combined subtype and 22% the inattentive subtype of ADHD.
Technique	Genotyping was carried out using standard PCR methods and analysed on 2% agarose. Detection rate of DRD4 genotypes was 87.5% for the VNTR and 96% for the 5' 120 bp duplication.
Analysis Method	The family genotypes were analysed by single marker transmission disequilibrium test (TDT), and haplotype-based haplotype relative risk test (HHRR) run in UNPHASED http://portal.litbio.org/Registered/Menu. UNPHASED was also used to calculate haplotype associations for phase-certain haplotypes (TDTPHASE) and for uncertain haplotypes (HHRR) in addition linkage disequilibrium between the markers.
Result Description	No evidence of association of ADHD with either polymorphism in this population was observed. The DRD4 gene markers investigated were not found to be associated with ADHD in this Taiwanese sample.

Other variant reported by this study (count: 2)

Variant Name	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
DRD4 promoter duplication 120bp		120bp	allelic TDT P-value=0.71; HHRR P-value=0.73 allelic TDT P-value=0.71; HHRR P-value=0.73	global and allele-specific tests of association were non-significant	Non-significant
DRD4 exon3 VNTR			allelic TDT P-value=0.55; HHRR P-value=0.55 allelic TDT P-value=0.55; HHRR P-value=0.55	global and allele-specific tests of association were non-significant	Non-significant

Genes reported by this study (count: 1)