Human Herpesvirus Infections: a risk factor for neurodevelopmental disorders in children?

Neurodevelopmental disorders (NDD), such as autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Tourette syndrome (TS), significantly impact the quality of life for affected children and their families. While their etiology is complex and multifactorial, recent studies have explored the potential role of viral infections, particularly human herpesviruses (HHV), as triggering or aggravating factors.

This study examines the causal relationship between HHV infections and these neurodevelopmental disorders.

What is the connection between neurodevelopmental disorders and viral infections?

Using European genomic datasets, researchers investigated genetic variants associated with HHV infections (HSV, VZV, EBV, CMV) and analyzed their potential impact on ASD, ADHD, and TS. These analyses revealed no significant association between genetically predicted HHV infections and the risk of NDD. Similarly, sensitivity analyses (leave-one-out method) showed no major bias linked to specific variants.

Additionally, twenty-seven observational studies were reviewed to evaluate the clinical links between HHV infections and NDD. These findings, though more variable, highlighted a significant association between CMV, HHV-6, and ASD. Regarding EBV and CMV, an increased risk of TS was identified in the Chinese population. Finally, no clear correlation between HSV or HHV-7 and NDD was established.

Towards a better understanding of herpesviruses’ role in neurodevelopmental disorders

While genetic analyses do not establish direct causality between HHV infections and NDDs, observational data suggest significant links between certain human herpesviruses (CMV, HHV-6, and EBV) and specific neurodevelopmental disorders. These disparities may be explained by factors such as geographical variations, differences in detection methods, or individual genetic susceptibilities.