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	Chen CK, 200312740596
Citation	Chen C. K., Chen S. L., Mill J., Huang Y. S., Lin S. K., Curran S., Purcell S., Sham P. and Asherson P. (2003) "The dopamine transporter gene is associated with attention deficit hyperactivity disorder in a Taiwanese sample." Mol Psychiatry, 8(4): 393-6.
Study Design	family-based
Study Type	Candidate-gene association study
Sample Size	110 probands and their parents
Predominant Ethnicity	Mongoloid
Population	China
Gender	92 (83.6%) were males
Age Group	Children/Adolescents : 5-15 years

Detail Info

Summary	They analysed the DAT1 polymorphism in a sample of 110 Taiwanese probands with a DSM-IV diagnosis of ADHD and found evidence of increased transmission of the 10-repeat allele using TRANSMIT. These data give rise to a similar odds ratio to that observed in Caucasian poplulations despite a far higher frequency of the risk allele in this Taiwanese population; 82.3% in the un-transmitted parental alleles and 94.5% in the ADHD probands. These data support the role of DAT1 in ADHD susceptibility among Asian populations.
Total Sample	The sample consists of 110 children with ADHD diagnosed between the ages of 5-15 years and available parents. They genotyped a total of 59 complete parent-offspring trios, 45 duos with only one parent and six singletons with no parental DNA available.
Sample Collection	ADHD cases were ascertained from the Child Psychiatric Clinics in the Chang Gung Memorial Hospital in Taipei area, Taiwan.
Diagnosis Description	A 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	The VNTR polymorphism was amplified on an MJ PTC-225 thermal cycler (MJ Research) in a hot-start protocol involving an initial 5-min denaturing step at 95^oC, followed by 38 cycles of 93^oC for 1 min and 72^oC for 1 min. Primers used were 5'- TGT GGT GTA GGG AAC GGC CTG AG-3' and 5'- CTT CCT GGA GGT CAC GGC TCA AGG-3'. The reaction mix included 75 ng of genomic DNA, 1.5mM MgCl₂, 20mM dNTP's, 10mM 10XPCR Buffer (PE Applied Biosystems) and 1 unit of Taq polymerase (added separately 30s into the denaturing step). PCR products were run out on a 2% agarose gel.
Analysis Method	Tests of association were performed using the haplotype- based haplotype relative risk (HHRR), the transmission disequilibrium test (TDT) and TRANSMIT. Calculations for the association power table were made using the genetic power calculator (http:// statgen.iop.kcl.ac.United Kingdom) which is described in detail by Sham et al.
Result Description	They analysed the DAT1 polymorphism in a sample of 110 Taiwanese probands with a DSM-IV diagnosis of ADHD and found evidence of increased transmission of the 10-repeat allele using TRANSMIT (X²=10.8, 1 d.f., p=0.001, OR=2.9, 95% CI 1.4-6.3). These data give rise to a similar odds ratio to that observed in Caucasian poplulations despite a far higher frequency of the risk allele in this Taiwanese population; 82.3% in the un-transmitted parental alleles and 94.5% in the ADHD probands. These data support the role of DAT1 in ADHD susceptibility among Asian populations.

Other variant reported by this study (count: 1)

Genes reported by this study (count: 1)