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	Galvez, J. M.,201324362847
Citation	Galvez JM, Forero DA, Fonseca DJ, Mateus HE, Talero-Gutierrez C, Velez-van-Meerbeke A (2013) Evidence of association between SNAP25 gene and attention deficit hyperactivity disorder in a Latin American sample. Atten Defic Hyperact Disord. doi: 10.1007/s12402-013-0123-9
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	73 cases and 152 controls
Predominant Ethnicity
Population	Colombia
Gender	20.5% female in cases and 50.7% female in controls
Age Group	Children/Adolescents : Mean (SD)(Year) = 8.6 (2.3) for patients and 16.9 (7.1) for controls

Detail Info

Summary	Attention deficit hyperactivity disorder (ADHD) is one of the most highly heritable behavioral disorders in childhood, with heritability estimates between 60 and 90 %. Family, twin and adoption studies have indicated a strong genetic component in the susceptibility to ADHD. The synaptosomal-associated protein of molecular weight 25 kDa (SNAP25) is a plasma membrane protein known to be involved in synaptic and neural plasticity. Animal model studies have shown that SNAP25 gene is responsible for hyperkinetic behavior in the coloboma mouse. In recent studies, several authors reported an association between SNAP25 and ADHD. In this study, we used a case-control approach to analyze the possible association of two polymorphisms of SNAP25 for possible association with ADHD in a sample of 73 cases and 152 controls in a Colombian children population. Polymorphisms are located in 3' untranslated region of SNAP25, positions T1065G and T1069C. We found a significant association with the GT haplotype (rs3746554\|rs1051312) of SNAP25 (p = 0.001). Evidence of association was also found for the G/G genotype of rs3746554 (p = 0.002) and C/C genotype of rs1051312 (p = 0.009). This is the first study in a Latin American population. Similar to other studies, we found evidence of the association of SNAP25 and ADHD.
Total Sample	Therefore, children included as cases had at least one of the following: (1) children with a DSM-IV checklist applied to parents with C6 criteria of inattention and a percentile C85 in the attention score of BASC applied to parents or teachers or (2) children with a DSMIV checklist applied to parents with C6 criteria of hyperactivity and a percentile C85 in the hyperactivity score of BASC applied to parents or teachers. The Wechsler Intelligence Scale for Children-Revised was applied to all subjects, and children with a score below 70 were excluded from the study. Those children with neurological disorders such as a cognitive disability (i.e., mental retardation), cerebral palsy, severe sensory handicaps such as blindness and deafness, Tourette syndrome or psychiatric disorders were also excluded. Controls were subjects who did not have symptoms of ADHD and did not meet the criteria for ADHD.
Sample Collection	Cases and controls were selected from an observational study carried out in public and private schools in Bogota¡ä, Colombia (South America).
Diagnosis Description	Cases were elected among children who had positive symptoms for ADHD according to the DSM-IV checklist (validated in Colombia), and if they were suspected to have ADHD according to questionnaires applied to teachers and parents. The diagnosis was confirmed applying the behavior assessment system for children (BASC) scale. Because of a low concordance in parent/teachers scores, we separately analyzed the attention and hyperactivity scores of parents and teachers for the final sample.
Technique	PCR and RFLP
Analysis Method	Association analysis were performed using the genetic statistic program PLINK.
Result Description	A significant association was detected (P = 0.002) between the rs2652511 C-allele with ADHD. In addition, the 6-repeat allele of Int8 VNTR was associated with higher inattention scores (P = 0.034). The haplotype analysis including DAT1 3'-UTR and Int8 VNTR polymorphisms did not reveal associations with ADHD susceptibility or severity dimensions. These findings extend to adult samples previous findings from children samples on the role of the rs2652511 polymorphism in the promoter region of DAT1 as a risk factor for ADHD susceptibility.

SNPs reported by this study (count: 2)

SNP	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
rs3746544	G/T		Allele P-value = 0.003 after Bonferroni correction; genotype P-value = 0.002 after Bonferroni correction.	Significant association was observed Significant association was observed	Significant
rs1051312	C/T		Allele P-value = 0.05 after Bonferroni correction; genotype P-value = 0.009 after Bonferroni correction.	Significant association was observed Significant association was observed	Significant

Genes reported by this study (count: 1)