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	Salatino-Oliveira, A., 201222897819
Citation	Salatino-Oliveira A., Genro J. P., Chazan R., Zeni C., Schmitz M., Polanczyk G., Roman T., Rohde L. A. and Hutz M. H. (2012) "Association study of GIT1 gene with attention-deficit hyperactivity disorder in Brazilian children and adolescents." Genes Brain Behav, 11(7): 864-8.
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	521 children with ADHD and 125 unaffected controls
Predominant Ethnicity	Caucasian
Population	Brazilian
Gender	76.8% male cases and 62.4% male controls
Age Group	Children/Adolescents : mean age=10.6 (SD=3.16) years of cases, mean age=11.8 (SD=3.31) years of controls

Detail Info

Summary	The aim of this study was to determine if this association also occurs in a sample of Brazilian children with ADHD. No effect of GIT1 genotypes on ADHD susceptibility was observed in the case-control analysis. The odds ratios (ORs) were 0.75 (P = 0.184) for the CT genotype and 1.09 (P = 0.862) for the TT genotype. In addition, the adjusted OR of the CT+TT genotypes vs. the CC genotype was also estimated (P = 0.245). There were no dimensional associations between the GIT1 genotypes and both hyperactivity and /impulsivity, and only hyperactivity Swanson, Nolan and Pelham Scale-Version IV (SNAP-IV) scores (P = 0.609 and P = 0.247, respectively). The transmission/disequilibrium test indicated that there was no over-transmission of rs550818 alleles from parents to ADHD children (z = 0.305; P = 0.761).
Total Sample	This study included 646 unrelated Brazilian children and adolescents (521 children with ADHD and 125 unaffected controls). Most of the patients presented the combined type (65.3%) followed by the inattentive subtype (25.4%). Of the 521 childrenwith ADHD, the most common comorbidity was oppositional defiant disorder (37.4%) followed by anxiety disorders (29.0%), mood disorders (15.2%) and conduct disorder (11.9%).
Sample Collection	The largest subsample of cases was composed of 421 children with ADHD recruited in the Child and Adolescent Psychiatric Division at the Hospital de Cl¨ªnicas de Porto Alegre (HCPA). The remaining 100 subjects were children with ADHD inattentive type. This group was ascertained from 12 public schools.
Diagnosis Description	a first evaluation was performed with a semi-structured interview (Schedule for Affective Disorders and Schizophrenia for School-Age Children, Epidemiological Version; K-SADS-E) (Orvaschel 1985), which was modified to assess DSM-IV criteria. Second, a discussion of each diagnosis that had been derived through the K-SADS-E was performed by a clinical committee chaired by one of the authors (L.A.R.). Third, a clinical evaluation of ADHD and comorbid conditions using DSM-IV criteria was assessed by a child psychiatrist who had previously received the results of the K-SADS-E. The remaining 100 subjects were children with ADHD inattentive type. Inclusion and diagnostic criteria for this sample were similar to those described above and have been fully described elsewhere (Schmitz et al . 2006).
Technique	The rs550818 polymorphism was genotyped using a TaqMan SNP Genotyping Assay-on-Demand according to the manufacturer's recommended protocol.
Analysis Method	Allele frequencies were estimated by counting. Deviations from Hardy-Weinberg equilibrium were assessed by the ¦Ö2 test. Comparisons among variables were performed using the ¦Ö2, Fisher's exact or Mann-Whitney U-test (for quantitative variables without normal distributions).
Result Description	No effect of GIT1 genotypes on ADHD susceptibility was observed in the case-control analysis. The odds ratios (ORs) were 0.75 (P = 0.184) for the CT genotype and 1.09 (P = 0.862) for the TT genotype. In addition, the adjusted OR of the CT+TT genotypes vs. the CC genotype was also estimated (P = 0.245). There were no dimensional associations between the GIT1 genotypes and both hyperactivity and /impulsivity, and only hyperactivity Swanson, Nolan and Pelham Scale-Version IV (SNAP-IV) scores (P = 0.609 and P = 0.247, respectively). The transmission/disequilibrium test indicated that there was no over-transmission of rs550818 alleles from parents to ADHD children (z = 0.305; P = 0.761). We conclude that rs550818 is not associated with ADHD in this Brazilian sample. More studies are required before concluding that this polymorphism plays a role in ADHD susceptibility.

SNPs reported by this study (count: 1)

SNP	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
rs550818	C/T		TT genotype: P-value=0.862, OR=1.087, 95% CI=0.42¨C2.79 for model 1; P-value=0.245, OR=0.782, 95% CI=0.516¨C1.184 for model 2; CT genotype: P-value=0.184, OR=0.749, 95% CI=0.49¨C1.15 for model 1; CC genotype: OR=1 for model 1 and 2. TDT P-value=0.761, z =0.305	Adjusting for gender, age and IQ score, no effect of GIT1 ge...... Adjusting for gender, age and IQ score, no effect of GIT1 genotypes on ADHD susceptibility was observed in the case-control analysis. With the TDT test, we did not detect the overtransmission of any rs550818 allele (C or T ) from parents to ADHD children. More...	Non-significant

Genes reported by this study (count: 1)