Autosomal dominant frontotemporal lobar degeneration: From genotype to phenotype

Abstract

Frontotemporal lobar degeneration (FTLD) is the most frequent dementia in presenile population. It presents with different syndromes, including frontotemporal dementia (FTD), primary non-fluent aphasia (PNFA), and semantic dementia (SD). Motor neuron disease often co-occur with FTLD. In the last few years, different autosomal dominant mutations have been demonstrated to be the cause of the familial aggregation frequently reported in FTLD. Major causal genes so far discovered include microtubule-associated protein tau (MAPT), progranulin (GRN), and chromosome 9 open reading frame (C9ORF) 72. Mutations in MAPT are generally associated with early onset and with the FTD phenotype, whereas mutations in GRN and C9ORF72 are associated with high clinical heterogeneity and age at disease onset. In addition, other genes are linked to rare cases of familial FTLD. Moreover, the use of next-generation sequencing approach allowed the identification of disease modifier (risk) genes such as common variants in the transmembrane protein 106b.