The association of SHANK3 gene polymorphism and autism.

BACKGROUND: Autism spectrum disorder (ASD) and Autism are both general terms for a group of complex disorders of brain development. These disorders are characterized by difficulties in social interaction, verbal and nonverbal communication and repetitive behaviors. Many genes have been shown to be involved in Autism. SHANK3 (SH3 and multiple ankyrin repeat domain 3) is a member of the highly conserved Shank/ProSAP family of synaptic scaffolding proteins. SHANK3 is suggested as a strong candidate gene for the pathogenesis of Autism and its loss results in disruption of synaptic function. The rs9616915 SNP, which directly affects SHANK3 gene function of splicing regulation and protein structure damage, is a non-synonymous SNP (T>C) that found in exon 6, leads to substitution of Isoleucine to Threonine. The present study was aimed to evaluate whether rs9616915 polymorphism of SHANK3 are related with the susceptibility to Autism.

METHODS: Samples were obtained from 90 patients diagnosed with Autism and 100 controls subjects and genotyped by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). The results of this study showed that there is a significant association in genotype distribution between cases and controls (P=0.0001).

RESULTS: Our findings revealed that individuals with TC genotypes were associated with increased risk of Autism disorder (OR=4.35, 95% CI: 2.15-8.80, P=0.0001) but no significant differences were found in allele distributions (P=0.1).

CONCLUSIONS: Our results indicated that the SHANK3 rs9616915 polymorphism is associated with increased risk of Autism. Larger studies with more patients and controls are needed to confirm the results.