Summary |
The aim of the present study was to investigate the association between the genetic type and alleles for the HTR1A gene in Korean children with ADHD. The sample consisted of 142 ADHD children and 139 control children. We diagnosed ADHD according to the Diagnostic and Statistical Manual of Mental Disorders-4th edition. ADHD symptoms were evaluated with Conners' Parent Rating Scales and Dupaul Parent ADHD Rating Scales. Blood samples were taken from the 281 subjects, DNA was extracted from blood lymphocytes, and polymerase chain reaction was performed for HTR1A polymorphism. Alleles and genotype frequencies were compared using the chi-square test. We compared the allele and genotype frequencies of HTR1A gene polymorphism in the ADHD and control groups. |
Total Sample |
Subjects were excluded from the study if there was any evidence of conduct disorder, mood disorder, anxiety disorder, Tourette's disorder, pervasive development disorder, mental retardation (IQ<70), and neurological disorders, including epilepsy. None of the children who participated in the study has ever undergone drug treatment before the evaluation. Subjects were included from our sample if they had a score over two standard deviations from the norm on the tests for ADS (T-score > 70). We excluded children with a high score of depressive symptoms and anxiety symptoms. Subjects with high anxiety scores (a Spielberger trait/state anxiety scale score > 47/49) on the Korean version of Spielberger trait-state anxiety scale for children were excluded, and subjects with high depression scores (Kovacs depression inventory score > 29) on Kovacs depression inventory for children were also excluded. |
Sample Collection |
A questionnaire was conducted with about 16,000 elementary school students in a city whose population is about 500,000 from September 2008 and August 2010. For the control group, 139 children in the same area were selected by matching the sex and age of the subjects in the patient group. |
Diagnosis Description |
An interview was performed randomly with the children whose Korean version of the Dupaul ADHD Rating Scales (K-ARS) (Kim et al., 2002) score was 19 or higher, and 142 ADHD children who consented to the genetic study were selected. For both the patient and control groups, a clinical evaluation and the Diagnostic and Statistical Manual of Mental Disorders-4th edition (DSM-IV) diagnosis were performed by a child psychiatrist. In addition, a professional clinical psychologist performed a comprehensive psychological test,including an intelligence test, on each subject. |
Technique |
The HTR1A single nucleotide polymorphism (SNP) was genotyped by polymerase chain reaction according to the protocol originally described by a study (Serretti et al., 2007) and HTR1A rs10042486(T/C), rs1423691(T/C), rs6295(G/C), rs878567(T/C) were genotyped by Illumina, Inc. (San Diego, CA) through the use of their Integrated Bead Array System). |
Analysis Method |
We performed independent t tests for age, chi-square tests for sex, and chi-square tests to compare the results of the control group and the ADHD group through the frequency of the genotypes and alleles. SPSS PC software (version 15.0) was used for the statistical analysis and the signi?cance level was set to the p-value being less than 0.05. |
Result Description |
There was a signi?cant correlation among the frequencies of the rs10042486 (OR=1.55, 95%CI=1.02-2.30,p=0.041), rs1423691(OR =1.55,95%CI=1.02-2.30,p=0.041),and rs878567(OR=1.60,95%CI=1.06-2.43,p=0.027) alleles of HTR1A, but the ?nal conclusions are not de?nite. Follow-up studies with larger patient or pure subgroups are expected. These results suggested that HTR1A might be related to ADHD symptoms. |