Lack of association of OXTR variants with autism spectrum disorders in a south Indian population

Abstract

Background: Absence of an effective treatment strategy for autism spectrum disorder (ASD) has necessitated the need for extensive research on oxytocin (OT) and oxytocin receptor gene (OXTR). However, studies on the role of genetic variants in OT and OXTR gene in determining ASD risk is not equivocal owing to the disparities across different ethnicities. We investigated the association of previously reported genetic variants in the OXTR gene with ASD individuals in a south Indian population. Methods: We recruited 222 subjects (110 ASD participants and 112 controls), from south India based on the diagnosis by the DSM-IV criteria. We genotyped single nucleotide polymorphisms (SNPs) rs2254298, rs2254295, rs60902022 and rs53576 in the OXTR gene and the allelic association between ASD participants and controls were determined. Results: We observed higher minor allelic frequency for the OXTR SNPs, which were in linkage disequilibrium in our population. However, the controls failed to exhibit any significant allelic association at rs2254298 (p=0.784), rs2254295 (p=0.661), rs60902022 (p=0.726), rs53576 (p=0.989) or genotypic association at rs2254298 (p=0.78), rs2254295 (p=0.66), rs60902022 (p=0.72), rs53576 (p=0.99) with ASD participants. Similarly, haplotype analysis also failed to prove any association. Conclusion: We suspect that the disparity in the allele frequencies for the SNPs selected in this study across populations might be the reason behind the lack of association as observed in previous studies. Thus, extensive research is necessary. Our study revealed that among south Indians, the rs2254298, rs2254295, rs60902022 and rs53576 SNPs in OXTR gene are unlikely to contribute to the susceptibility of ASD.