Suspected non-Alzheimer's disease pathophysiology (SNAP) is a biomarker-based concept referring to individuals with a normal amyloid-β protein (Aβ) marker (A−), and abnormal tau (T+) and/or neurodegeneration (N+) marker(s), defined by cerebrospinal fluid (CSF) or imaging markers.1,2 In the present paper, SNAP is defined as normal CSF Aβ-42 levels and abnormal CSF p-tau levels (A−T+). This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.