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 C, 200111304829
Citation	Xu C., Schachar R., Tannock R., Roberts W., Malone M., Kennedy J. L. and Barr C. L. (2001) "Linkage study of the alpha2A adrenergic receptor in attention-deficit hyperactivity disorder families." Am J Med Genet, 105(2): 159-62.
Study Design	family-based
Study Type	Candidate-gene association study
Sample Size	288 individuals from 94 nuclear families
Predominant Ethnicity	Caucasian
Population	Canada
Age Group	Children/Adolescents : 7-16 years

Detail Info

Summary	They examined the possibility that the gene for the alpha2A adrenergic receptor (ADRA2A) is linked to ADHD by testing a polymorphism located in the promoter region of the ADRA2A gene in a sample of 94 nuclear families with an ADHD proband. They found no evidence for linkage of the ADRA2A gene with ADHD, using the transmission disequilibrium test in this set of families.
Total Sample	They genotyped 288 individuals from 94 nuclear families from the Toronto area. These families consisted of 76 trios (consisting of father, mother, and affected child) and 18 parent/child pairs. There were 24 affected siblings used in the analysis. Twenty of the families had one additional affected child in addition to the proband, and two families had two affected children in addition to the proband. Subjects for the study were children seven to 16 years of age diagnosed with ADHD according to DSM-IV criteria [USAn Psychiatric Association, 1994] at the Hospital for Sick Children, Toronto, Ontario.
Sample Collection	94 nuclear families with 288 individuals were collected from the Toronto area
Diagnosis Description	The diagnostic assessment and inclusion and exclusion criteria have been described previously [Barr et al., 1999, 2000a, 2000b]. Briefly, information on ADHD and comorbid disorders was obtained using a semi-structured interview for parents (Parent Interview for Child Symptoms, PICS-IV; Schachar&Ickowicz, unpublished) and teachers (Teacher Telephone Interview- IV, TTI; Tannock&Schachar, unpublished). This information was supplemented by evidence about behavior, development, and medical history derived from standardized parent and teacher questionnaires; the Ontario Child Health Survey Scales-Revised [Boyle et al., 1993] and the Conners Parent and Teacher Rating Scales-Revised [Conners, 1997]. Of the subjects that were used in this study, 57% of the children were of the combined subtype, 19% were of the hyperactive/impulsive subtype, and 24% were of the primarily inattentive subtype.
Technique	A 522 bp fragment from the promoter region was amplified by PCR using the primers ADRA2A-Msp I F (5'-TCA CAC CGG AGG TTA CTT CCC TCG-3') at position -1417 and ADAR2A-Msp I R (5'-TCC GAC GAC AGC GCG AGT T-3') at position -913 [Lario et al., 1997].
Analysis Method	The Extended TDT software package ETDT version 1.4 [Sham and Curtis, 1995], was used for calculating the TDT statistic. The TDT statistic is used to detect linkage in the presence of linkage disequilibrium.
Result Description	They found no evidence for linkage of the ADRA2A gene with ADHD, using the transmission disequilibrium test in this set of families.

SNPs reported by this study (count: 1)

Genes reported by this study (count: 1)