The main clinical syndromes are frontotemporal dementia (FTD), semantic dementia (SD) and progressive non-fluent aphasia (PA).[1] FTLD can be divided neuropathologically into diseases with tau-positive inclusions and diseases with tau-negative and ubiquitin-positive inclusions.[2] A positive family history is present in 30–50% of FTLD cases.[3,4] Mutations in microtubule-associated protein tau (MAPT), progranulin (PGRN) and charged multi-vesicular body protein 2B (CHMP2B) are associated with the autosomal dominant form of the disease. The gene discussed is MAPT; the disease is semantic dementia.