Experimental evidence has linked PCSK9 dysfunction to cerebral β‐amyloid production and neuronal cell death—both hallmarks of AD.39 PCSK9 may also promote neurogenesis during development,40 so any impact on AD risk could potentially be mediated by establishing “brain reserve” in early life,41 as opposed to a hastening of AD pathogenesis in adulthood. Here, PCSK9 is linked to Alzheimer disease.