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	de Cerqueira CC, 201120864182
Citation	de Cerqueira C. C., Polina E. R., Contini V., Marques F. Z., Grevet E. H., Salgado C. A., da Silva P. O., Picon F. A., Belmonte-de-Abreu P. and Bau C. H. (2011) "ADRA2A polymorphisms and ADHD in adults: possible mediating effect of personality." Psychiatry Res, 186(2-3): 345-50.
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	403 adult patients and 232 controls
Predominant Ethnicity	Caucasian
Population	Brazil
Gender	48.2% of females and 51.8% of males
Age Group	Adults : average age: 34 years

Detail Info

Summary	As the effect of other relevant clinical characteristics could be a possible source, they studied three polymorphisms in the ADRA2A gene in 403 adult patients with ADHD assessed in relation to comorbidity and personality characteristics, as well as in 232 controls. The diagnosis followed DSM-IV criteria, and personality dimensions were evaluated with the Temperament and Character Inventory (TCI). There were no significant differences in allele and genotype frequencies between cases and controls. Patients carrying the G allele of rs1800544 presented lower scores in harm avoidance, and carriers of the T allele of rs553668 had more novelty seeking and less harm avoidance and persistence. Additionally, the haplotype carrying the G-GT alleles was associated with lower scores in harm avoidance and persistence, and higher scores in novelty seeking compared to other haplotypes.
Total Sample	The patient sample included 403 adult Brazilians of European descent, from the ADHD adult outpatient clinic of Hospital de Clinicas of Porto Alegre. The average age was 34 years, with 48.2% of females and 51.8% of males. The control sample (n=232) was recruited from a blood bank in the vicinity of the hospital. Ethnicity in the control sample was deduced exactly in the same way as in the patient's sample.
Sample Collection	The study recruited patients from the adult ADHD outpatient clinic of the Hospital de Clinicas de Porto Alegre (a major teaching hospital in Southern Brazil). The control sample was recruited from a blood bank in the vicinity of the hospital.
Diagnosis Description	The diagnostic procedures for ADHD followed the DSM-IV criteria (USAn Psychiatric Association, APA, 1994), using the Portuguese version of the 'Schedule for Affective Disorders and Schizophrenia, Epidemiological Version for school age Children' (K-SADS-E) (Mercadante et al., 1995) assessing present and worst lifetime episodes of DSM-IV psychiatric disorders in children (Ambrosini, 2000). These patients were classified in the combined subtype (54.8%), inattentive subtype (39.4%) or hyperactive/impulsive subtype (5.8%).
Technique	DNA was extracted by a salting out method (Lahiri and Nurnberger, 1991). The polymorphism rs1800544 in the ADRA2A gene was amplified with PCR conditions adapted from Lario et al. (1997) and Lima et al. (2007), followed by digestion with MspI and genotyping in a 10% polyacrylamide gel stained with ethidium bromide. The other two polymorphisms (rs1800545 and rs553668) were amplified using the primers and conditions suggested for the TaqMan allelic discrimination system (Applied Biosystems 7500 Real Time PCR System).
Analysis Method	The genotype, allele and haplotype frequency comparisons between ADHD patients and controls, as well as analysis of other categorical variables were performed with the chi-square test. No multiple comparison correction was applied to this study.
Result Description	There were no significant differences in allele and genotype frequencies between cases and controls. Patients carrying the G allele of rs1800544 presented lower scores in harm avoidance, and carriers of the T allele of rs553668 had more novelty seeking and less harm avoidance and persistence. Additionally, the haplotype carrying the G-GT alleles (rs1800544-rs1800545-rs553668) was associated with lower scores in harm avoidance and persistence, and higher scores in novelty seeking compared to other haplotypes.

SNPs reported by this study (count: 3)

SNP	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
rs1800545	G/A		chi-square test P-value=0.054, X²=3.709 for allele frequencies; chi-square test P-value=0.028, X²=7.147 for genotype frequencies, P-value=0.104, X²=2.639 when the analysis combined the rare AA with GA genotype	genotypes of the rs1800545 polymorphism revealed a slight di...... genotypes of the rs1800545 polymorphism revealed a slight difference, but when the analysis combined the rare AA with GA genotype, the difference was not significant; they did not consider the significant result as conclusive because of the very small frequency of the AA genotype More...	Significant
rs553668	C/T		chi-square test P-value=0.194, X²=1.687 for allele frequencies; chi-square test P-value=0.206, X²=3.158 for genotype frequencies	no significant differences in allele and genotype frequencie...... no significant differences in allele and genotype frequencies were found between patients and controls in this study More...	Non-significant
rs1800544	C/G		chi-square test P-value=0.464, X²=0.536 for allele frequencies; chi-square test P-value=0.695, X²=0.729 for genotype frequencies	no significant differences in allele and genotype frequencie...... no significant differences in allele and genotype frequencies were found between patients and controls in this study More...	Non-significant

Genes reported by this study (count: 1)