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	Franke B, 200818802924
Citation	Franke B., Hoogman M., Arias Vasquez A., Heister J. G., Savelkoul P. J., Naber M., Scheffer H., Kiemeney L. A., Kan C. C., Kooij J. J. and Buitelaar J. K. (2008) "Association of the dopamine transporter (SLC6A3/DAT1) gene 9-6 haplotype with adult ADHD." Am J Med Genet B Neuropsychiatr Genet, 147B(8): 1576-9.
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	216 patients and 528 controls
Predominant Ethnicity	Caucasian
Population	the Netherlands
Gender	105 males (48.6%)
Age Group	Adults : 18-62 years (mean age=36)

Detail Info

Summary	In the current study they attempted to replicate in adults with ADHD the reported association of a 10-6 SLC6A3-haplotype, formed by the 10-repeat allele of the variable number of tandem repeat (VNTR) polymorphism in the 3' untranslated region of the gene and the 6-repeat allele of the VNTR in intron 8 of the gene, with childhood ADHD. In addition, they wished to explore the role of a recently described VNTR in intron 3 of the gene. Two hundred sixteen patients and 528 controls were included in the study. They found a 9-6 SLC6A3-haplotype, rather than the 10-6 haplotype, to be associated with ADHD in adults. The intron 3 VNTR showed no association with adult ADHD. Their findings converge with earlier reports and suggest that age is an important factor to be taken into account when assessing the association of SLC6A3 with ADHD. If confirmed in other studies, the differential association of the gene with ADHD in children and in adults might imply that SLC6A3 plays a role in modulating the ADHD phenotype, rather than causing it.
Total Sample	216 patients had been referred for assessment of ADHD and 528 controls were obtained from the Nijmegen Biomedical Study. The control group was frequency-matched for gender with the patient group. Patients and controls were of Caucasian ethnic background.
Sample Collection	Patients had been referred for assessment of ADHD to the outpatient clinic of GGZ Delfland in Delft, to Parnassia, psycho-medical centre in The Hague, or to the department of Psychiatry at the Radboud University Nijmegen Medical Centre in Nijmegen, the Netherlands. Controls were obtained from the Nijmegen Biomedical Study.
Diagnosis Description	a semi-structured diagnostic interview for ADHD and comorbid disorders, the Dutch version of structured diagnostic interviews for retrospective diagnosis of childhood onset ADHD and current symptoms was used; a Dutch version of the DSM-IV ADHD Rating Scale, based on the 18 DSM-IV items for ADHD, was used to assess current ADHD symptoms during the last 6 months
Technique	Genotyping of the VNTRs in the 3' UTR and intron 8 has been described earlier [Brookes et al., 2006b; Boonstra et al., 2008]. The 63 base pair (bp) VNTR in intron 3 of the gene was genotyped using a PCR-based method.
Analysis Method	Genotype frequencies were compared between cases and controls using a chi-square test. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using SPSS (version 14.0). Haplotype association analyses were done using the haplo.score function implemented in haplo.stats. This analysis was corrected for multiple testing by applying the simulate=TRUE parameter in haplo.score which gives simulated p values.
Result Description	They found a 9-6 SLC6A3-haplotype, rather than the 10-6 haplotype, to be associated with ADHD in adults. The intron 3 VNTR showed no association with adult ADHD. Their findings converge with earlier reports and suggest that age is an important factor to be taken into account when assessing the association of SLC6A3 with ADHD. If confirmed in other studies, the differential association of the gene with ADHD in children and in adults might imply that SLC6A3 plays a role in modulating the ADHD phenotype, rather than causing it.

Other variant reported by this study (count: 3)

Variant Name	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
SLC6A3 intron8 VNTR			Pearson chi-square P-value=0.731, OR=1 for 6/6 genotype freq...... Pearson chi-square P-value=0.731, OR=1 for 6/6 genotype frequency, OR=0.93 for 6/5 genotype frequency, OR=0.73 for 5/5 genotype frequency More...	genotype analysis did not show significant differences between cases and controls	Non-significant
SLC6A3 intron3 VNTR			Pearson chi-square P-value=0.809, OR=1 for 7/7 genotype freq...... Pearson chi-square P-value=0.809, OR=1 for 7/7 genotype frequency, OR=0.975 for 7/8 genotype frequency, OR=0.691 for 8/8 genotype frequency More...	genotype analysis did not show significant differences between cases and controls	Non-significant
SLC6A3 3'-UTR VNTR			Pearson chi-square P-value=0.085, OR=1 for 10/10 genotype fr...... Pearson chi-square P-value=0.085, OR=1 for 10/10 genotype frequency, OR=1.27 for 10/9 genotype frequency, OR=1.98 for 9/9 genotype frequency More...	genotype analysis did not show significant differences between cases and controls	Non-significant

Genes reported by this study (count: 1)