Frontotemporal Lobar Degeneration (Pick's Syndrome) refers to the group of progressive dementias including Frontotemporal Dementia (FTD), Progressive non-fluent aphasia (PNFA) and semantic dementia. These dementias are the result of the rapid decline of brain cells which control behaviour, thinking and communication in the frontal and temporal lobes of the brain. In 2008, research in the genetics and molecular biology of FTLD showed that most cases of familial FTLD are the result of mutations in the progranulin (PGRN) gene, located on the human chromosome 17. Up until recent years it was thought that FTLD was caused by the mutation of the micro-tubule associated protein tau (MAPT) gene, also located on chromosome 17, however it was unknown why many cases of FTLD showed no mutation on the MAPT gene. A clinical-pathological investigation was conducted in which the clinical characteristics of two FTLD families with PGRN mutations were compared with patients found to have MAPT mutations. Patients with PGRN mutations exhibited a phonological (speech sound) deficiency, while MAPT mutation patients had language abnormalities and prominent behavioural dysfunctions associated with semantic dementia.
This advance in research has provided evidence for the link between FTD, PNFA and semantic dementia, and has raised the possibility of identifiable clinical differences between Frontotemporal Lobar Degeneration patients with MAPT and PGRN mutations.
http://brain.oxfordjournals.org/cgi/content/abstract/129/11/3091
Eileen H. Bigio, MD, American Association of Neuropathologists, Inc
http://neuro.pathology.pitt.edu/webstuff/Journal%20Club/ftld%20update%20bigio%202008.pdf
