Intrafamilial clinical phenotypic heterogeneity with MAPT gene splice site IVS10+16C>T mutation

Two families with frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) resulting from the microtubule associated protein tau (MAPT) gene IVS10+16C>T splice site mutation are reported, members of which showed variable clinical phenotypes at presentation. Possible explanations for the intra- and interfamilial clinical heterogeneity associated with this MAPT mutation are discussed.