Vitamin D Receptor Gene Polymorphisms Associated with Childhood Autism

Background: Autism spectrum disorder (ASD) is a group of heterogeneous, behaviorally defined disorders whereby currently no biological markers are common to all affected individuals. A deregulated immune response may be contributing to the etiology of ASD. The active metabolite of vitamin D(3) has an immunoregulatory role mediated by binding to the vitamin D receptor (VDR) in monocyte, macrophages, and lymphocytes. The effects of vitamin D and interaction with the VDR may be influenced by polymorphism in the VDR gene. Methods: Genetic association of four different VDR polymorphisms (Apa-I, Bsm-I, Taq-I, Fok-I) associated with susceptibility to the development of autism in children was investigated. Results: We uniquely found an association between the presence of the T allele at position Taq-I and presence of the a allele at position Apa-I of the VDR gene with decreased ASD incidence. There was also an association between female gender and the presence of the T allele. We found no statistical significant correlation between VDR single nucleotide polymorphisms (SNPs) and vitamin D(3) concentration in serum of ASD children. Conclusion: Genetic polymorphism in two SNP in VDR may be correlated with development of ASD symptoms by influencing functionality of vitamin D(3) metabolism, while vitamin D(3) levels were not significantly different between ASD and non-ASD children.