ERVW-1 and amyotrophic lateral sclerosis: Since then, accumulated findings have included elevated (up to 3-fold increase) expression of retroviral genes in the brains of ALS patients; the presence of HERV-K-env protein in the cerebrospinal fluid (CSF), and neurons; HERV-K env protein in neuronal extracellular vesicles (NEV) of patients, with higher concentrations in patients with worse clinical conditions; higher levels of antibody concentration against HERV-K in CSF and serum of ALS patients, and more (Douville et al., 2011; Li et al., 2015; Arru et al., 2018; Li et al., 2022; Steiner et al., 2022).