Association with tryptophan hydroxylase 2 gene polymorphisms and autism spectrum disorders in Korean families

► The associations between SNPs in TPH2 and Korean ASD were examined. ► We found a significant association at the rs2129575 with ASD susceptibility. ► TPH2 polymorphisms may influence ASD susceptibility and the phenotypic impairments. It was performed a family-based association study of 6 single nucleotide polymorphisms (SNPs) from the TPH2 with autism spectrum disorder (ASD) in 151 Korean trios. We found a significant association at the rs2129575 with ASD susceptibility (corrected p=0.006). Furthermore, after conducting with the quantitative scores in the Autism Diagnostic Interview—Revised, there were associations between restricted, repetitive, and stereotyped patterns of behavior (preoccupation with parts of objects or nonfunctional elements of materials) in ASD and SNPs in TPH2. These results suggest that TPH2 polymorphisms influence the phenotypic impairments of ASD and enhance ASD susceptibility.