[Clinical, pathological, and genetic characteristics of frontotemporal dementia and parkinsonism linked to chromosome 17 with mutations in the MAPT and PGRN]

Abstract

We reviewed the clinical, neuropathological, and genetic findings in patients with frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) with mutations in microtubule-associated protein tau (MAPT) and progranulin (PGRN). Research on FTDP-17 has greatly progressed over the years. Clinically, FTDP-17 is clinically characterized by autosomal dominant frontotemporal dementia, with or without parkinsonism. Two pathological variants of FTDP-17 are seen: one characterized by tau aggregation in neurons and glial cells, and the other, by ubiquitin-positive inclusions in neurons. Mutations in the MAPT gene have been identified as a cause of familial tau-positive FTDP-17 (MAPT), whereas mutations in the gene encoding PGRN, which is located 1.7 Mb from the MAPT gene on chromosome 17, have been identified in familial ubiquitin-positive FTDP-17 (PGRN). Recent studies have identified 44 different mutations in more than 100 families with FTDP-17 (MAPT), and 66 different mutations in more than 100 families with FTDP-17 (PGRN). Although cases of FTDP-17 have been reported worldwide, FTDP-17 (PGRN) has not yet been seen in Japan. The discovery of monogenic forms of neurodegenerative diseases is important for understanding the pathogenesis of these diseases. The findings of future research may facilitate the understanding of the causes of FTDP, and further improve diagnostic tools and help develop novel preventive methods and treatments for not only the genetic but also the sporadic form of neurodegenerative disorders.