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	Castellanos FX, 19989774777
Citation	Castellanos F. X., Lau E., Tayebi N., Lee P., Long R. E., Giedd J. N., Sharp W., Marsh W. L., Walter J. M., Hamburger S. D., Ginns E. I., Rapoport J. L. and Sidransky E. (1998) "Lack of an association between a dopamine-4 receptor polymorphism and attention-deficit/hyperactivity disorder: genetic and brain morphometric analyses." Mol Psychiatry, 3(5): 431-4.
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	41 cases and 56 controls
Predominant Ethnicity	Caucasian
Population	USA
Age Group	Children/Adolescents : case: mean age=9.7 (SD=2.6) years; control: 6-52 years (mean age=17.6, SD=9.1)

Detail Info

Summary	Polymorphisms of the dopamine 4 receptor (DRD4) affect receptor binding, and one allele with seven tandem repeats in exon 3 (DRD47R) has been associated with ADHD. They examined this putative association in 41 children with severe ADHD and 56 healthy controls who were group matched for ethnicity and sex. The frequency of the DRD47R allele did not vary by diagnosis (0.220 vs 0.205 in patients and controls, respectively). Behavioral and brain anatomic MRI measures, previously found to discriminate patients from controls, did not differ significantly between subjects having and those lacking a DRD47R allele. These data do not support the reported association between DRD47R and the behavioral or brain morphometric phenotype associated with ADHD.
Total Sample	The sample consisted of 41 children with ADHD, with a mean age of 9.7 (SD=2.6) years, and 56 healthy controls recruited from the community, with a mean age of 17.6 (SD=9.1) years, ranging from 6-52 years.
Sample Collection	Children with ADHD were determined to be stimulant responders in a double-blind stimulant study described elsewhere with the exception of one 16-year-old female who participated only in a brain imaging study. Healthy subjects were recruited from the community.
Diagnosis Description	The DSM-III-R diagnosis of ADHD was confirmed by a Diagnostic Interview for Children and Adolescents-Revised (DICA-R) inteview with a parent and Conners Parent and Teacher Rating Scales.
Technique	The DRD4 exon 3 VNTR polymorphic site was amplified using PCR.
Analysis Method	Differences in allele frequency were tested by comparison to the chi-square distribution. Significance level for this replication study was set at 0.05 with all comparisons two-tailed.
Result Description	The frequency of the DRD47R allele did not vary by diagnosis (0.220 vs 0.205 in patients and controls, respectively). Behavioral and brain anatomic MRI measures, previously found to discriminate patients from controls, did not differ significantly between subjects having and those lacking a DRD47R allele. These data do not support the reported association between DRD4*7R and the behavioral or brain morphometric phenotype associated with 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	2-7 repeats	7R	chi-square P-value=0.81, X² (1df) =0.06 for the f...... chi-square P-value=0.81, X² (1df) =0.06 for the frequency of 7R allele between cases and controls, P-value=0.66, X² (1df) =0.19 for the frequency of short (2-5 repeats) vs long (6 or 7 repeats); genotypic chi-square P-value=0.31, X² (8df) =9.35, P-value=0.25, X² (1df) =1.31 for the frequency of genotype 4.4 vs 4.7 More...	There was no significant differences between patients and psychiatrically screened controls in the frequency of the DRD*7R allele nor in any other of the DRD4 alleles; patients and controls did not differ significantly in frequency of individual genotypes, in the frequency of genotype 4.4 vs 4.7 or in the frequency of short vs long alleles	Non-significant

Genes reported by this study (count: 1)