The genetic and pathological classification of familial frontotemporal dementia.

Abstract
FRONTOTEMPORAL dementia (FTD) is a clinical diagnosis based on progressive personality change and language impairment related to frontotemporal lobar atrophy. It is a frequent cause of dementia, particularly in the younger age group, accounting for between 12% and 20% of all dementia cases.1 Pick disease is the archetypal pathological form of FTD. It is characterized pathologically by the presence of swollen α-B-crystallin–positive neurons (Pick cells), and argyrophilic, tau-positive round inclusions (Pick bodies) that are particularly numerous in the granule cells of the hippocampal dentate fascia and the superficial layers of the frontotemporal neocortex. Pick disease is sometimes also used as a clinical term for patients presenting with a progressive frontal syndrome or language disorder, and as a diagnosis for neurological conditions with radiologic frontotemporal lobar atrophy; strictly, however, Pick disease should be reserved for pathologically diagnosed disease.