MAPT and early-onset autosomal dominant Alzheimer disease: Tau, a microtubule-associated intracellular protein located in neuronal axons, has emerged as a potential biomarkers for AIS,8 demonstrating a significant correlation with the infarct size.9 Phosphorylation of tau is regulated in the developing foetal brain10,11 into adulthood, where it plays a physiological role in the assembly and stabilisation of axonal microtubule as well as synaptic structure.12, –14 Tau hyperphosphorylation is recognised as a hallmark of Alzheimer disease (AD) as part of neurofibrillary tangles.13,15