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 (DRD4*7R) 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 DRD4*7R 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 DRD4*7R allele. These data do not support the reported association between DRD4*7R 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 DRD4*7R 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 DRD4*7R 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)
Gene |
Statistical Values/Author Comments |
Result of Statistical Analysis |
DRD4 |
There were no significant differences between cases and cont......
There were no significant differences between cases and controls in the frequency of any allele and genotype
More...
|
Non-significant
|