This mutation results in the loss of the C‐terminal region of the endopeptidase neprilysin (NEP) protein (OMIM #120520), which inactivates a broad spectrum of peptide substrates, such as enkephalins, neurokinin A, substance P, bradykinin, endothelin, somatostatin, and more others, including amyloid‐β (Aβ) protein, which accumulates in Alzheimer's disease (AD). This evidence concerns the gene MME and Alzheimer disease.