Genetic Features of MAPT, GRN, C9orf72 and CHCHD10 Gene Mutations in Chinese Patients with Frontotemporal Dementia

Background: Mutations in microtubule associated protein tau (MAPT), progranulin (GRN), chromosome 9 open-reading frame 72 (C9orf72) and CHCHD10 genes have been reported causing frontotemporal dementia (FTD) in different populations. However, collective analysis of mutations in these four genes in Chinese FTD patients has not been reported yet. Methods: The aim of this study was to investigate the genetic features of Chinese patients with MAPT, GRN, C9orf72 or CHCHD10 gene mutations in an FTD cohort recruited from multi clinical centers in Shanghai metropolitan areas, China. MAPT, GRN and CHCHD10 genes were analysed by direct sequencing, and C9orf72 hexanucleotide repeat expansion was analysed by repeat-primed PCR in 82 patients with sporadic FTD. The identified gene variants were screened in 400 age matched controls. Results: We found one known pathogenic variant (rs63750959) and one novel mutation (NG_007398.1: g.120962C>T; H299Y) of MAPT gene, one novel variant (c.750C>A; D250E) of GRN gene and two novel mutations in CHCHD10 gene (c.63C>T, no AA change; c.71G>A, P24L). No abnormal C9orf72 gene hexanucleotide repeat expansion was identified in this cohort. Collectively, genetic testing could discover 4.9% sporadic FTD patients with genetic causes. In addition, MAPT and CHCHD10 might be more important genes affecting Chinese with FTD.