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	Cho, S. C., 201222993527
Citation	Cho, S. C., J. W. Son, B. N. Kim, J. W. Kim, H. J. Yoo, J. W. Hwang, D. Y. Cho, U. S. Chung and T. W. Park (2012). "Serotonin 2A Receptor Gene Polymorphism in Korean Children with Attention-Deficit/Hyperactivity Disorder." Psychiatry Investig 9(3): 269-277.
Study Design	case-control and family-based
Study Type	Candidate-gene association study
Sample Size	189 patients and 150 controls
Predominant Ethnicity	Mongloid
Population	Korean
Gender	166 male and 23 female patients, 131 male and 19 female controls
Age Group	Children/Adolescents : mean age=9.2, SD=2.3 years of probands, mean age=9.4, SD=0.6 years of controls

Detail Info

Summary	The purpose of this study was to investigate the association between the T102C polymorphism in the serotonin 2A receptor gene and attention-deficit/hyperactivity disorder (ADHD) in Korean patients. A total of 189 Korean children with ADHD as well as both parents of the ADHD children and 150 normal children participated in this study. DNA was extracted from blood samples from all of the subjects, and genotyping was conducted. Based on the allele and genotype information obtained, case-control analyses were performed to compare the ADHD and normal children, and Transmission disequilibrium tests (TDTs) were used for family-based association testing (number of trios=113). Finally, according to the significant finding which was showed in the case-control analyses, the results of behavioral characterastics and neuropsychological test were compared between ADHD children with and without the C allele.
Total Sample	189 ADHD patients who satisfied these selection and exclusion criteria and agreed to cooperate in the study, and 113 pairs of biological parents of these patients who were able to cooperate in the blood sampling and other research were selected as the study subjects. Because 3 patients did not receive results from the genetic analysis due to an error during the analysis, they were excluded from the association analysis; therefore, a total of 186 patients were assessed.
Sample Collection	ADHD outpatients who visited the Child and Adolescent Psychiatric Departments at 4 hospitals were selected for the study based on the following factors: 1) an age more than 5 years old; 2) diagnosis of ADHD using the DSM-IV diagnostic criteria and semi-structured interviews; and 3) a total score on the Parent ADHD Rating Scale (Korean ADHD Rating Scale; K-ARS) under the 90th percentile cutoff point. As the normal control group, 150 students were selected from one elementary school in Seoul and another in Jeonju after excluding children according to the following criteria: 1) having major medical/neurological/psychiatric diseases, as determined through parent surveys; 2) exhibiting serious behavioral problems, as determined through telephone consultations with their teachers; 3) presenting a total K-ARS score falling above the 90th percentile cutoff point; and 4) having an IQ of 70 or less (overall intelligence was estimated through vocabulary and block design subtests from the KEDI-WISC intelligence assessment).
Diagnosis Description	diagnosis of ADHD using the DSM-IV diagnostic criteria and semi-structured interviews. The clinical and neuropsychological assessment tools used in this study were as follows: Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version-Korean Version (K-SADS-PL-K); Korean Educational Development Institute-Wechsler Intelligence Scale for Children (KEDI-WISC); Korean ADHD Rating Scale-IV for Parents and Teachers (K-ARS); Korean Child Behavior Checklist (K-CBCL); Continuous Performance Test (CPT)
Technique	The 5-HTR2A gene T102C polymorphism was analyzed using a chip-based MALDI-TOF mass spectrometry platform (Sequenom, Inc., CA). The general test method described in the basic protocol provided by the manufacturer was used.
Analysis Method	a chi-square test was also performed to evaluate the association analysis between the case-control groups, whereas for the family-based association analysis, a TDT was performed using McNemar's chi-square test under the hypothesis that specific alleles are inherited more favorably. This study included only cases in which the patient-father-mother trio participated in the analyses. SPSS 10.0 for Windows was used for the statistical analyses, and the significance level was set at p<0.05.
Result Description	In the case-control analyses, statistically significant differences were detected in the frequencies of genotypes containing the C allele (chi(2)=4.73, p=0.030). In the family-based association study, TDTs failed to detect linkage disequilibrium of the T102C polymorphism associated with ADHD children. In the ADHD children, both the mean reaction time and the standard deviation of the reaction time in the auditory continuous performance test were longer in the group with the C allele compared to the group without the C allele. The results of this study suggest that there is a significant genetic association between the T102C polymorphism in the serotonin 2A receptor gene and ADHD in Korean children.

Other variant reported by this study (count: 1)

Variant Name	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
HTR2A T102C	T/C		genotypic P-value=0.078, allelic P-value=0.153, grouping P-v...... genotypic P-value=0.078, allelic P-value=0.153, grouping P-value=0.899 with or without T allele, grouping P-value=0.030 with or without C allele between ADHD probands and controls; genotypic P-value=0.049, allelic P-value=0.181, grouping P-value=0.882 with or without T allele, grouping P-value=0.023 with or without C allele between the probands of ADHD combined type and controls; TDT P-value=1.000, X²=0.00, df=1 More...	The frequency distribution of the 3 genotypes among the entire ADHD patient group and the control group did not reveal any statistical differences, though the T/C type tended to appear more frequently in the patient group. Moreover, the frequency distributions of the groups according to the presence of T allele were also examined, and no statistical difference was detected between the case and the control group. However, comparison of the distributions between the case and control groups according to the presence of C allele showed that there were significant differences between the groups with and withoutC allele. In addition, an association analysis was conducted between the control group and the combined-type ADHD subtype. The results indicated that there were significant differences in the frequency distributions of the 3 genotypes between the case group and the control group. Furthermore, comparison of the distributions between the case and control groups according to alleles also showed that there were significant differences between the groups with and without C allele. However, there were no significant differences in allele frequency or classification according to the presence of the T allele. A TDT analysis was conducted on the entire family group of the patient-parent trios, but the selective transmission of a specific allele was not observed. Likewise, no selective transmission of a specific allele was observed in the trios of the combined-type ADHD patient families.	Significant

Genes reported by this study (count: 1)