Comparative Expression Analysis of Human Endogenous Retrovirus Elements in Blood Samples of Children with Autism Spectrum Disorder

Abstract

Autism spectrum disorder (ASD) is a highly diverse group of developmental disorders with a multicausal etiology and a strong genetic basis. About 8% of the human genome consists of human endogenous retrovirus elements (HERVs). HERV transcription appears to be altered not only in specific brain regions but also in the peripheral blood of patients with psychiatric conditions such as schizophrenia, multiple sclerosis (MS), ASD, and different types of cancer. This study aims to investigate the blood-based expression of five distinct human endogenous retrovirus elements in a patient cohort of 31 children with Autism Spectrum Disorder (ASD) and a control group of 27 children with typical development. The comparative HERV expression analysis in 31 children with a diagnosis of ASD and 27 age- and sex-matched healthy controls was performed via a whole transcriptome sequencing approach combined with qRT-PCR analysis. Two HERV-encoded genes: HERV-P env, and HERV-R env, were found to be significantly downregulated in the group of children with ASD. Another HERV gene, HERV-W pol appeared to be significantly upregulated. Receiver operating characteristic (ROC) analysis indicated that the observed changes in transcript levels of HERV-P env and HERV-R env can discriminate between ASD patients and healthy controls with considerable sensitivity and specificity. Our results alongside a large number of expression studies conducted by other researchers suggest that human endogenous retrovirus elements may participate in important physiological processes and serve as key factors and markers for many conditions including ASD.