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	Xu X, 2005(b)16082690
Citation	Xu X., Mill J., Chen C. K., Brookes K., Taylor E. and Asherson P. (2005) "Family-based association study of serotonin transporter gene polymorphisms in attention deficit hyperactivity disorder: no evidence for association in UK and Taiwanese samples." Am J Med Genet B Neuropsychiatr Genet, 139B(1): 11-3.
Study Design	family-based
Study Type	Candidate-gene association study
Sample Size	197 subjects from United Kingdom, 212 subjects from Taiwan
Predominant Ethnicity	Caucasian, Mongoloid
Population	United Kingdom, China
Age Group	Children/Adolescents : United Kingdom sample: not mentioned; Taiwanese sample: 5-15 years

Detail Info

Summary	They investigated the association of these three markers (long-allele of a 44-base pair insertion/deletion polymorphism (5-HTTLPR), a variable number tandem repeat within intron 2, T-allele of a single base pair substitution in the 30-untranslated regions) in two samples of ADHD patients from the United Kingdom (n=197) and Taiwan (n=212), using within-family tests of association. No association was found between any of the three markers in either of the two populations. Although they found some evidence for the preferential transmission of a rare haplotype, they concluded that this most likely occurred by chance factors alone.
Total Sample	For the United Kingdom sample DNA was available from 197 ADHD probands, both parents in 133 families, and from only the mother in 64 families. The Taiwanese sample consisted of 212 children with ADHD diagnosed between the ages of 5 and 15 years. Both parents were available for 114 families, only the mother for 59 families and only the father for 23 families.
Sample Collection	For the United Kingdom sample DNA was available from 197 ADHD probands, both parents in 133 families, and from only the mother in 64 families. ADHD cases were ascertained from the Child Psychiatric Clinics in the Chang Gung Memorial Hospital in Taipei area, Taiwan.
Diagnosis Description	United Kingdom sample: cases were referred for assessment if they were thought by experienced clinicians to have a diagnosis of the combined subtype of ADHD under DSM-IV criteria, with no significant Axis I co-morbidity apart from oppositional defiant disorder (ODD) and conduct disorder (CD). Research criteria were established using standardized interview and application of operational criteria for DSM-IV combined type as described previously [Mill et al., 2004]. Taiwanese sample: A diagnosis of ADHD was made according to DSM-IV criteria following completion of a standard maternal interview [KIDDIE-SADS, Kaufman et al., 1997] and completion of parent and teacher Conner's revised rating scales [Conners, 1995]. In all 78% had the combined subtype and 22% the inattentive subtype of ADHD.
Technique	Genotyping followed routine procedures. The 5-HTTLPR promoter region polymorphism (44 base pair insertion/deletion) and the 17 base pair 'HTT-VNTR' polymorphism were genotyped using the methods described in Zoroglu et al. [2002]. The HTT-3'UTR-SNP was amplified using primers described in Kent et al. [2002].
Analysis Method	Genotype data was analyzed using the extended transmission disequilibrium test (ETDT) [Sham and Curtis, 1995] and the haplotype-based haplotype relative risk test (HHRR) [Terwilliger and Ott, 1992] on complete trios, and TRANSMIT for the analysis of the complete datasets including families with missing parental data [Clayton, 1999].
Result Description	No association was found between any of the three markers in either of the two populations. Although they found some evidence for the preferential transmission of a rare haplotype (long-allele/9-repeat-allele/T-allele; x²=4.5, P=0.034), they concluded that this most likely occurred by chance factors alone.

Other variant reported by this study (count: 3)

Variant Name	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
SLC6A4 intron2 VNTR			allelic ETDT P-value=0.497, X²=1.399 in UK sample...... allelic ETDT P-value=0.497, X²=1.399 in UK samples; allelic ETDT P-value=0.440, X²=1.644 in Taiwanese samples; allelic ETDT P-value=0.355, X²=2.071 in combined samples; allelic HHRR P-value=0.517, X²=1.318 in UK samples; allelic HHRR P-value=0.446, X²=1.615 in Taiwanese samples; HHRR P-value=0.381, X²=1.929 in combined samples; allelic TRANSMIT P-value=0.850, X²=0.324 in UK samples; allelic TRANSMIT P-value=0.706, X²=0.692 in Taiwanese samples; allelic TRANSMIT P-value=0.813, X²=0.413 in combined samples More...	there was no significant preferential transmission in UK samples, Taiwanese samples and combined samples	Non-significant
SLC6A4 3'-UTR G/T	G/T		allelic ETDT P-value=0.524, X²=0.405 in UK sample...... allelic ETDT P-value=0.524, X²=0.405 in UK samples; allelic ETDT P-value=0.345, X²=0.891 in Taiwanese samples; allelic ETDT P-value=0.943, X²=0.005 in combined samples; allelic HHRR P-value=0.543, X²=0.388 in UK samples; allelic HHRR P-value=0.335, X²=0.929 in Taiwanese samples; HHRR P-value=0.949, X²=0.004 in combined samples; allelic TRANSMIT P-value=0.906, X²=0.014 in UK samples; allelic TRANSMIT P-value=0.395, X²=0.723 in Taiwanese samples; allelic TRANSMIT P-value=0.971, X²=0.001 in combined samples More...	there was no significant preferential transmission in UK samples, Taiwanese samples and combined samples	Non-significant
5HTTLPR	short/long		allelic ETDT P-value=0.521, X²=0.412 in UK sample...... allelic ETDT P-value=0.521, X²=0.412 in UK samples; allelic ETDT P-value=0.497, X²=0.462 in Taiwanese samples; allelic ETDT P-value=0.943, X²=0.005 in combined samples; allelic HHRR P-value=0.546, X²=0.364 in UK samples; allelic HHRR P-value=0.530, X²=0.394 in Taiwanese samples; HHRR P-value=0.950, X²=0.004 in combined samples; allelic TRANSMIT P-value=0.689, X²=0.161 in UK samples; allelic TRANSMIT P-value=0.074, X²=3.192 in Taiwanese samples; allelic TRANSMIT P-value=0.696, X²=0.153 in combined samples More...	there was no significant preferential transmission of the long-allele in UK samples, Taiwanese samples and combined samples	Non-significant

Genes reported by this study (count: 1)