The oxytocin receptor gene polymorphism -rs237902- is associated with the severity of autism spectrum disorder: A pilot study.

INTRODUCTION: Previous studies showed the association of Autism Spectrum Disorder (ASD) and oxytocin receptor (OXTR) gene. We aimed to explore the OXTR gene single nucleotide polymorphisms (SNPs) across the ASD severity categories based on DSM-5.

METHOD: The whole encoding regions of the human OXTR gene were sequenced to identify the SNPs in 100 Turkish children with ASD. Genotypes of detected SNPs were also compared with the Childhood Autism Rating Scale (CARS) scores.

RESULTS: Disease severity of the patients carrying GA and AA genotypes (GA/AA) of rs237902 were found more severe compared to those carrying GG genotype (χ2  = 6.456, df = 2, p = .040). This finding was more powerful in boys (χ2  = 9.288, df = 2, p = .010). Similarly, GA/AA genotypes of rs237902 were found associated with higher CARS scores in boys (U = 650.5, r = 0.24, p = .021).

CONCLUSION: Significant relationship between the ASD severity categories of DSM-5 and rs237902 was shown for the first time.