MAPT and progressive non-fluent aphasia: The tau protein stabilizes microtubules,30,31 and over 50 MAPT mutations have been associated with frontotemporal dementia.32–34 Abnormally phosphorylated tau aggregates, which are the second most common form of pathological protein aggregate in frontotemporal dementia, are mostly associated with behavioural-variant frontotemporal dementia and progressive non-fluent aphasia subtypes.16 The ratio between phosphorylated tau (p-tau181) and total tau (t-tau) has been suggested for differentiation between molecular frontotemporal dementia subtypes.