Note! This is a brief overview of the molecular genetics of Frontotemporal dementia. Detailed information for lay persons, caregivers, physicians and researchers can be found on the web sites listed in the Links Section.
Frontotemporal degeneration ((FTD, OMIM entry 600274) is an adult-onset behavioral disturbance followed by frontal lobe dementia, parkinsonism, and amyotrophy in variable proportions. Genetic factors are involved in the majority of patients and in some cases FTD segregates as an autosomal dominant trait in families. In chromosome 17-linked FTD families, mutations in the gene encoding the microtubule associated protein tau (MAPT) and the granulin gene (GRN) are identified. In FTD populations the MAPT mutation frequency ranged from 8 to 50%, that of GRN from 5 to 26%. Also, mutations in the gene encoding the chromatin modifying protein 2B (CHMP2B) at chromosome 3p11.2 were identified in autosomal dominant FTD (OMIM entry 600795). Inclusion body myopathy with early-onset paget disease and frontotemporal dementia (IBMPFD) was associated with mutation in the valosin-containing protein gene (VCP) at chromosome 9p13-p12 (OMIM entry 167320) and amyotrophic lateral sclerosis (ALS) with FTD was linked to a locus at chromosome 9q21-q22 (OMIM entry 105550), in which the mutated gene remains to be identified.