Association analysis of the GABRB3 promoter variant and susceptibility to autism spectrum disorder

Objective: Several previous linkage and association studies and an expression analysis have suggested the gamma-aminobutyric acid type A receptor beta3 subunit (GABRB3) gene as an important candidate gene for autism. In addition, polymorphisms in the promoter region of GABRB3 might modulate the expression of this gene. In order to investigate the underlying mechanism of the role of GABRB3 in autism susceptibility, we designed a case-control study to analyze the association of the rs4906902 single nucleotide polymorphism (SNP) in the promoter region of the GABRB3 gene with autism spectrum disorder (ASD) in Iranian patients. Materials & methods: The rs4906902 polymorphism was genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The frequency of the risk allele and its association with disease was examined in 518 patients and 472 control individuals. Result: The results demonstrated that the genotype frequencies were in Hardy-Weinberg equilibrium in both the case and the control groups. The results shown that neither allelic frequencies nor genotypic distribution of the rs4906902 was significantly different between autism patients and healthy controls. In conclusion: It seems that the GABRB3 gene may influence the Autism susceptibility via a different SNPs in this gene. Also, another independent mechanisms like epigenetic effects should not be ignored when we want to explore the link between GABRB3 and ASD.