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	Faraone SV, 199910327912
Citation	Faraone S. V., Biederman J., Weiffenbach B., Keith T., Chu M. P., Weaver A., Spencer T. J., Wilens T. E., Frazier J., Cleves M. and Sakai J. (1999) "Dopamine D4 gene 7-repeat allele and attention deficit hyperactivity disorder." Am J Psychiatry, 156(5): 768-70.
Study Design	family-based
Study Type	Candidate-gene association study
Sample Size	27 ADHD adult patients and their families
Predominant Ethnicity	USA
Population	USA
Age Group	Adults

Detail Info

Summary	Family, twin, and adoption studies show attention deficit hyperactivity disorder (ADHD) to have a substantial genetic component, and some studies have reported an association between ADHD and the dopamine D4 (DRD4) gene. The authors recruited 27 triads that comprised an ADHD adult, his or her spouse, and their ADHD child. These triads were assessed for ADHD, and their DNA was genotyped for DRD4 alleles. A multiallelic transmission disequilibrium test suggested an association between ADHD and the DRD4 7-repeat allele. Among family members, the number of 7-repeat alleles predicted the diagnosis of ADHD. Prior reports of an association between ADHD and DRD4 generalize to families recruited through clinically referred ADHD adults. However, because there are some conflicting studies, further work is needed to clarify the role of DRD4 in the etiology of the disorder.
Total Sample	The families reported in this study were spouses and ADHD children of 27 ADHD adult patients.
Sample Collection	The families reported in this study were spouses and ADHD children of 27 ADHD adult patients from their psychopharmacology clinic (one spouse was also found to have ADHD).
Diagnosis Description	These adults had received a clinical diagnosis of ADHD and met DSM-IV criteria for ADHD when evaluated with the ADHD module from the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Epidemiologic Version, modified to assess DSM-IV criteria.
Technique	DNA strands were isolated from whole blood as described by Schumm et al.. The DRD4 gene contains a varying number of 48 base pair repeats within the gene. They used a method described by Lichter et al. and modified it by adding 7-deazaglutamyl transpeptidase (0.2 mM final concentration) and 10% dimethyl sulfoxide to the polymerase chain reaction cocktail.
Analysis Method	A multiallelic transmission disequilibrium test suggested an association between ADHD and the DRD4 7-repeat allele. Among family members, the number of 7-repeat alleles predicted the diagnosis of ADHD. To determine which alleles accounted for the significant result, they computed a chi-square statistic contrasting the cell numbers for each pair of nondiagonal cells in the transmission disequilibrium test table. For these analyses, they used a Bonferroni-corrected p value of 0.01. They used logistic regression to determine if, among family members, the number of 7-repeat alleles predicted the diagnosis of ADHD.
Result Description	A multiallelic transmission disequilibrium test suggested an association between ADHD and the DRD4 7-repeat allele. Among family members, the number of 7-repeat alleles predicted the diagnosis of ADHD.

Other variant reported by this study (count: 1)

Variant Name	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
DRD4 exon3 VNTR	2-8 repeats	7R	TDT P-value=0.03 indicating that one or more alleles were pr...... TDT P-value=0.03 indicating that one or more alleles were preferentially transmitted to the ADHD child; chi-square P-value=0.007, X²=7.4, df=1 for 7-repeat allele; logistic regression P-value=0.01, Z=2.5 for 7-repeat allele as a predictor of the diagnosis of ADHD More...	suggested an association between ADHD and the DRD4 7-repeat allele; the number of 7-repeat alleles predicted the diagnosis of ADHD	Significant

Genes reported by this study (count: 1)