In Alzheimer’s Disease (AD), tau exhibits pathological hyperphosphorylation [1,2], allowing both histological diagnosis by use of tau antibodies against disease specific phosphorylation sites [3,4] and, to a certain extent, even in vivo diagnosis by determination of the protein’s phosphorylation status in cerebrospinal fluid [5,6]. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.