Frontotemporal dementia.
Frontotemporal dementia (FTD) is an uncommon but important form of degenerative disease. It may make up 50% of dementia cases presenting before age 60. The symptoms are related to the anatomic areas affected. Neary divided the clinical syndromes into "frontotemporal dementia," "progressive nonfluent aphasia," and "semantic dementia." However, the pathology may extend beyond the frontal and temporal lobes and additional symptoms may be found. Although most cases are sporadic, some cases are genetic. The best-known genetic mutation causing FTD is frontotemporal dementia with parkinsonism, linked to the microtubule-associated protein tau on chromosome 17. There are other known genes and chromosome loci related to FTD. The most common pathology found is frontotemporal degeneration with ubiquitin inclusions. In contrast, FTD with Pick bodies is rare. Although there are strategies to help patients and their families, there is no known treatment for the disease.