Although traditionally described as characteristic of Alzheimer’s disease, medial temporal lobe atrophy is commonly seen in FTD [2] with the hippocampus often strikingly affected, particularly in carriers of mutations in the MAPT gene [3, 4], where volume loss occurs 15 years before expected onset [5], and there is a faster rate of atrophy compared with other genetic forms of FTD [6, 7]. The gene discussed is MAPT; the disease is frontotemporal dementia.