Ras-like without CAAX 2 (RIT2): a susceptibility gene for autism spectrum disorder.

Ras-like without CAAX2 (RIT2) which encodes a GTP-binding protein has recently been reported as a new susceptibility gene for Autism Spectrum Disorders (ASD) in a genome-wide association study. Since the gene is suggested to be involved in the pathogenesis of different neurological diseases, we investigated the association of two single nucleotide polymorphisms (SNP) rs16976358 and rs4130047 of this gene with ASD in Iranian patients. A total of 1004 individuals, comprising 532 ASD cases and 472 healthy subjects participated in this study. Allele frequency analyses showed significant over-presentation of rs16976358-C allele in cases versus controls (P < 0.0001). In addition, rs16976358 CC genotype (OR (95% CI) =3.57(1.72-7.69) and P < 0.0001) and rs4130047 CC genotype (OR (95% CI) =0.64(0.43-0.97) and P = 0.035) were associated with ASD in recessive inheritance model. Besides, haplotype analysis demonstrated an association between the C/T haplotype block (rs16976358/rs4130047) and ASD (OR (95%CI) = 0.44 (0.31-0.62), P < 0.0001). Altogether, our findings provided additional confirmation for the RIT2 gene participation in ASD risk and suggested the rs16976358 variant as a possible genetic risk factor for this disorder.