Semantic dementia associated with mutation V363I in the tau gene.

A 46-year-old woman who presented with prosopagnosia was clinically evaluated. Results of neuropsychological measures showed severe impairment in oral naming with anomia and a marked deficit in naming and recognition of famous faces. The clinical diagnosis was semantic dementia (SD). Genetic testing revealed a missense mutation V363I in exon 12 of the microtubule-associated protein tau (MAPT) gene. This is the description of an association between a mutation in the MAPT gene and a case of SD. The same mutation was recently described in a case of progressive non-fluent aphasia, but the prominent presenting feature in tau gene mutation cases is the behavioral variant of frontotemporal dementia, with typical symmetrical frontotemporal atrophy.