Recent studies have shed light on the possible role of the HERV-K and HERV-W env genes in neurodegenerative diseases, including Alzheimer’s disease (Antony et al., 2004; Perron et al., 2005; Li et al., 2015; Ibba et al., 2018). Here, ERVW-1 is linked to early-onset autosomal dominant Alzheimer disease.