sSEZ6 is released from full‐length SEZ6 through the action of the protease BACE1 (also known as β‐secretase) (Pigoni et al, 2016), which is a key drug target in AD as it catalyzes the first step in the generation of the pathogenic Aβ peptide (Vassar et al, 2014). Here, BACE1 is linked to Alzheimer disease.