Study Report

Basic Info
Reference |
Ohadi M, 200616782077
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Citation |
Ohadi M., Shirazi E., Tehranidoosti M., Moghimi N., Keikhaee M. R., Ehssani S., Aghajani A. and Najmabadi H. (2006) "Attention-deficit/hyperactivity disorder (ADHD) association with the DAT1 core promoter -67 T allele." Brain Res, 1101(1): 1-4.
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Study Design |
case-control |
Study Type |
Candidate-gene association study |
Sample Size |
110 patients and 120 controls |
Predominant Ethnicity |
Iranian |
Population |
Iran |
Gender |
77 males and 33 females subjects, 80 males and 40 females controls |
Age Group |
Children/Adolescents
:
case: mean age 10 years (SD=5.0); control: 12 years (SD=4.0)
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Detail Info
Summary |
In this study, they examined whether either allele of the DAT1 core promoter -67 functional polymorphism is associated with ADHD in a case/control study. The allele and genotype frequencies of the polymorphism were studied in 110 patients and 120 controls, which were matched on the basis of sex, age and ethnicity. The genotype frequencies in the patients group were as follows: AA 19.2%; AT 65.2%; TT 15.4% vs. the genotype frequencies in the control group: AA 47.5%; AT 43.3%; TT 9.2%. The T allele of the -67A/T polymorphism revealed an ~1.56-fold excess in the patients group comparing with the controls. For the first time, these findings provide tentative evidence of the contribution of the DAT1 gene core promoter polymorphism to the etiopathophysiology of ADHD at least in the Iranian population that they have studied. Further work is warranted to confirm this finding and to assess its generalization to other ethnic groups. |
Total Sample |
110 unrelated Iranian subjects (77 males and 33 females) with ADHD were recruited for the study from the Child Psychiatry Clinic of the Rassool Akram Hospital-Iran Medical Sciences University and two private clinics in Tehran. One hundred and twenty unrelated Iranian normal children (80 males and 40 females) were randomly selected as controls. The two groups were matched on the basis of age, sex, and ethnic origin. The mean age of the patient and control groups was 10 (SD=5) years and 12 (SD=4) years, respectively. |
Sample Collection |
110 unrelated Iranian subjects with ADHD were recruited for the study from the Child Psychiatry Clinic of the Rassool Akram Hospital-Iran Medical Sciences University and two private clinics in Tehran. One hundred and twenty unrelated Iranian normal children were randomly selected as controls. |
Diagnosis Description |
All the patients in this study met the following criteria using Diagnostic and Statistical Manual of Mental Disorders (DSM-IV): six symptoms of inattention and/or hyperactivity/impulsiveness either in the home or school setting as determined by clinical interview; evidence of pervasiveness, defined as a minimum of four symptoms in the noncriterion setting; and onset before 7 years of age. The interviews were supplemented with the Conners Parent and Teacher Rating Scales (Conners, 1997) to assess the severity of disorder in each subject. |
Technique |
A 14 ml buccal sample was drawn from each subject. DNA was extracted using standard techniques and subsequently used as a template for the determination of DAT1 -67A/T alleles by polymerase chain reaction as described previously (Rubie et al., 2001). |
Analysis Method |
The Chi-square test was employed to compare frequency differences of the -67A/T alleles and genotypes between the groups studied. A P value of <=0.02 was considered significant, implementing the Bonferroni 0.5 mean correction to the conventional significant P value of <0.05. |
Result Description |
The genotype frequencies in the patients group were as follows: AA 19.2%; AT 65.2%; TT 15.4% vs. the genotype frequencies in the control group: AA 47.5%; AT 43.3%; TT 9.2% [X2=20.73, df=2, P<=0.0001]. The T allele of the -67A/T polymorphism revealed an ~1.56-fold excess in the patients group comparing with the controls [X2=14.50, df=1 (P<=0.001)]. For the first time, these findings provide tentative evidence of the contribution of the DAT1 gene core promoter polymorphism to the etiopathophysiology of ADHD at least in the Iranian population that they have studied. |

Other variant reported by this study (count: 1)
Variant Name |
Allele Change |
Risk Allele |
Statistical Values |
Author Comments |
Result of Statistical Analysis |
SLC6A3 promoter -67A/T |
A/T |
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chi-square test P-value<=0.0001, X2(1df)=14.50 fo......
chi-square test P-value<=0.0001, X2(1df)=14.50 for T allele; chi-square test genotypic P-value<=0.0001, X2(2df)=20.73
More...
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significant association between the T allele and ADHD and a significant skew in the distribution of the genotypes was detected between the two groups |
Significant
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Genes reported by this study (count: 1)
Gene |
Statistical Values/Author Comments |
Result of Statistical Analysis |
SLC6A3 |
the findings provided tentative evidence of the contribution......
the findings provided tentative evidence of the contribution of the SLC6A3 gene core promoter polymorphism to the etiopathophysiology of ADHD at least in the Iranian population
More...
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Significant
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