For example, patients with MAPT mutations and relatively focal anterior temporal lobe damage have, on average, slower rates of overall brain atrophy and survive substantially longer compared with patients with GRN mutations associated with widespread intrahemispheric damage [68]; interhemispheric asymmetry increases with advancing disease in association with GRN mutations [17]; but MAPT and GRN mutations produce similar local rates of atrophy within key structures such as the hippocampus [69]. This evidence concerns the gene GRN and Brain atrophy.