Sec and Cys share many similarities, and selenium and sulfur are in the same group of elements in the periodic table, and share some properties, so it is understandable that SELENOM, as well as the other selenoproteins containing the CXXU motif, may act as metal regulators, so they may also modulate metal-induced Aβ aggregation and neurotoxicity in AD. This evidence concerns the gene SELENOM and Alzheimer disease.