The role of the CNTNAP2 gene in the development of autism spectrum disorder

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental disorder in which genetic and environmental factors interact in its development. Research suggests that the contactin associated protein 2 (CNTNAP2) gene may play a role in ASD pathophysiology, yet more studies involving human participants and animal models of autism are needed. One such model may be the use of prenatal valproic acid (VPA) model to induce autism-like behaviors in offspring rats. The aim of this study was twofold: (1) to examine the association of the CNTNAP2 gene rs2710102 variant with ASD in children; and (2) to examine the effect of prenatal exposure to VPA on Cntnap2 gene expression in the rat brain. The study included 167 children of European ancestry—81 diagnosed with ASD (20 girls, 61 boys; age 4.9 ± 1.4 years) and 86 controls (44 girls, 42 boys; 5.1 ± 1.2 years). In vivo experiments were conducted in 80 rats (40 with the VPA model of autism), with Cntnap2 gene expression analysis in the amygdala, hippocampus, prefrontal cortex, and cerebellum. Results demonstrated that the frequency of the CNTNAP2 gene rs2710102 GG genotype was significantly higher in children with ASD when compared with controls (33.3 vs 19.8%; OR=2.03, 95%CI [1.004, 4.102], p = 0.035), although, potentially due to bias in cohort selection, in the ASD children this polymorphism did not meet Hardy-Weinberg expectations (χ² =5.40, p = 0.02). In addition, Cntnap2 gene expression was significantly lower (p < 0.01) in the amygdala and hippocampus of VPA rats when compared with controls, regardless of sex. These results support previous research and provide evidence for the CNTNAP2 gene as a risk factor for ASD.