Expression of Syncytin-1 outside the placenta has been reported, capable of activating a pro-inflammatory and autoimmune cascade through receptors CD14 and TLR4 (Toll-Like Receptor 4) on antigen-presenting cells, and also of triggering dysregulation of T-lymphocytes in multiple sclerosis (MS) [74]. The gene discussed is ERVW-1; the disease is multiple sclerosis.