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	Simsek M, 200616545000
Citation	Simsek M., Al-Sharbati M., Al-Adawi S. and Lawatia K. (2006) "The VNTR polymorphism in the human dopamine transporter gene: improved detection and absence of association of VNTR alleles with attention-deficit hyperactivity disorder." Genet Test, 10(1): 31-4.
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	92 cases and 110 controls
Predominant Ethnicity	Omani
Population	Oman
Age Group	Children/Adolescents

Detail Info

Summary	The human dopamine transporter (DAT1) gene contains a variable number tandem repeat (VNTR) in its 3'- untranslated region because of repetition of a 40-bp core sequence. Methods available for the diagnosis of this polymorphism are limited in number. They have developed a new polymerase chain reaction (PCR) test, which is similar to that described originally by Vandenbergh's group, but provides a better detection of the VNTR alleles in the human DAT1 gene. Using two independent PCR methods, they have determined the distribution of VNTR alleles in 110 healthy Omani subjects, and in 92 children with attention-deficit hyperactivity disorder (ADHD). The frequency of the risk allele (DAT1*10) was similar in the healthy subjects and ADHD cases, indicating absence of association of this allele with ADHD in Oman.
Total Sample	This study included 110 healthy Omani blood donors at Sultan Qaboos University Hospital (SQUH) as control subjects, and 92 Omani children attending the child and adolescent psychiatry clinic at SQUH as ADHD cases.
Sample Collection	Omani
Diagnosis Description	The diagnosis of ADHD in children was according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM-IV) criteria, which included a diagnostic questionnaire that was completed by the parents/guardians of each child in the presence of an attending child psychiatrist.
Technique	Five milliliters of ethylenediamine tetraacetic acid (EDTA)- blood were collected from each subject and genomic DNA was extracted from the frozen blood using a standard salting out procedure (Miller et al. 1988). The VNTR region of the DAT1 gene was amplified from the genomic DNA using two independent polymerase chain reactions (PCR) to minimize possible genotyping errors. Primers used in one PCR system were as described by Vandenbergh et al. (1992) (D1 forward, 5'-TGT GGT GTA GGG AAC GGC CTG AG-3' and D2 reverse, 5'- CTT CCT GGA GGT CAC GGC TCA AGG-3'). They used a new set of primers in the second PCR test (D3 forward: 5'-GCT CAG GCT ACT GCC ACT CAG GCA-3' and D4 reverse: 5'- GAT GTG GCA CGC ACC TGA GAG AAA-3'). More detailed description could be found in the original publication.
Analysis Method	statistical method was not mentioned in the original publication
Result Description	Using two independent PCR methods, they have determined the distribution of VNTR alleles in 110 healthy Omani subjects, and in 92 children with attention-deficit hyperactivity disorder (ADHD). The frequency of the risk allele (DAT1*10) was similar in the healthy subjects and ADHD cases, indicating absence of association of this allele with ADHD in Oman.

Other variant reported by this study (count: 1)

Genes reported by this study (count: 1)