Two-sample Mendelian randomization study does not reveal a significant relationship between cytomegalovirus (CMV) infection and autism spectrum disorder

Abstract

Background: Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting ~ 2% of children worldwide and is characterized by repetitive, stereotypical behaviours and impaired expressive communication. Cytomegalovirus (CMV) is considered a risk factor for ASD; however, published studies are usually limited by covering too few events and have different conclusions, indicating that the relationship between CMV infection and ASD remains elusive. Methods: To investigate the association between CMV infection and ASD, we conducted this 2-sample Mendelian randomization (MR) study using genome-wide association studies (GWAS) summary data from FinnGen and the IEU Open GWAS project. Results: Our results showed no significant relationship between all 3 CMV infections (unspecified cytomegaloviral diseases, anti-CMV IgG levels, and maternal CMV) and ASD. Conclusions: Our results indicate that CMV infection does not significantly increase ASD risk. These results show that the relationship between CMV infection and ASD remains elusive and needs to be further clarified.