TLR7 and early-onset autosomal dominant Alzheimer disease: It is worth noting that HERV-K (HML-2) RNA alone has been suggested to function as a ligand for toll-like receptors 7/8 (TLR7/8) in vitro in neurons and microglia, as well as in a mouse model of Alzheimer’s disease, and that TLR activation by HERV-K RNA induces neurotoxicity even in the absence of viral proteins [65].