The amyloid cascade hypothesis postulates that the deposition of the amyloid-β protein (the main component of the amyloid plaques) is the cause of Alzheimer’s disease and that neurofibrillary tangles, cell loss, vascular damage and dementia are a direct consequence.4 In keeping with the amyloid cascade hypothesis, a theoretical framework for the progression of biomarkers during the course of Alzheimer’s disease has been developed.5 Here, amyloid pathology is the first to appear, followed by tau pathology, neurodegeneration and, finally, cognitive decline. The gene discussed is MAPT; the disease is Alzheimer disease.