Ancient Viral DNA and the Genetic Risk for Neurodegenerative Diseases

Recent research conducted by the Institute of Psychiatry, Psychology & Neuroscience at King’s College London, in collaboration with Northwell Health, has uncovered a potential link between ancient viral DNA and the genetic risk for neurodegenerative diseases affecting the central nervous system. The study focuses on human endogenous retroviruses (HERVs), remnants from ancient retroviral infections that are now an integral part of our DNA. Using advanced genomic techniques, researchers identified specific HERV expression signatures associated with multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). **Multiple sclerosis** is one of the most common neurodegenerative diseases among young adults, affecting over 150,000 people in the UK alone. ALS, while less common, presents a more severe prognosis and affects approximately 5,000 people in the UK. The study, published in *Brain, Behavior, and Immunity*, marks a significant advancement in understanding the genetic factors contributing to these conditions. While previous studies have suggested a link between HERVs and neurodegenerative diseases, this research is among the first to identify specific HERVs associated with disease susceptibility. Researchers analyzed brain samples to examine the relationship between HERV expression and genetic risk factors for neurodegenerative diseases, including Parkinson’s and Alzheimer’s disease, MS, and ALS. Notably, they discovered distinct HERV expression patterns linked to ALS on chromosome 12 (MER61_12q14.2) and MS on chromosome 1 (ERVLE_1p36.32a). These viral sequences are believed to play a role in homophilic cell adhesion—critical for intercellular communication in the brain. However, no significant HERV signatures were identified for Alzheimer’s and Parkinson’s, hinting at the need for further investigation. The study’s findings suggest that ancient viral DNA is not merely a static remnant but may actively influence brain function in previously unknown ways. As the global prevalence of neurodegenerative diseases is expected to triple by 2050, these insights offer a promising avenue for developing targeted therapies. Understanding how HERVs affect brain function could pave the way for innovative treatments to mitigate the impact of these debilitating diseases. The research was supported by the National Institute for Health and Care, the National Institutes of Health, and The Psychiatry Research Trust.