ERVW-1 and multiple sclerosis: However, recent studies identified a number of ERVs, which retain intact coding potentials for gag, pol, and/or env genes, and some of them are reported to be associated with a range of normal physiology (e.g., placental morphogenesis) as well as pathogenic processes (e.g., multiple sclerosis, schizophrenia, injury, and chronic fatigue syndrome) [6–10].