Frontotemporal lobar degeneration: diversity of FTLD lesions.

ABSTRACT

Frontotemporal lobar degeneration (FTLD) is a heterogeneous group including both sporadic and familial diseases, characterized by a macroscopic alteration. It may correspond to various cognitive syndromes behavioral variant of frontotemporal dementia (bvFTD), progressive nonfluent aphasia, and semantic dementia. The neuropathologic classification is now based on identification of the protein that accumulates in neurons and glia Tau, TAR DNA Binding Protein 43 (TDP-43), and FUsed in Sarcoma (FUS). The disorders in which the corresponding proteins accumulate have been named FTLD-Tau, FTLD-TDP, and FTLD-FUS. FTLD-Tau includes sporadic cases (e.g. Pick's disease) and Tau mutations. FTLD-TDP are subdivided within four types (A, B, C, D) according to the shape and distribution of TDP-43 positive lesions within the associative frontal cortex. The FTLD-FUS group includes atypical FTLD with ubiquitinated lesions (FTLD-U), Neuronal Intermediate Filament Inclusion Disease (NIFID) and Basophilic Inclusion Body Disease (BIBD).