Pathological correlates of frontotemporal lobar degeneration in the elderly.

Frontotemporal lobar degeneration (FTLD) is generally recognised as a disorder with presenile onset (that is before 65 years of age) with only occasional cases presenting later than this. We set out to determine what proportion of cases of FTLD had late onset of disease and whether such cases of FTLD had distinctive clinical and neuropathological features as compared to cases with presenile onset. Within a combined Manchester and Newcastle autopsy series of 117 cases with pathologically confirmed FTLD (109/117 cases also met Lund Manchester clinical criteria for FTLD), we identified 30 cases (onset age range 65-86 years), comprising 25% of all FTLD cases ascertained in these two centres over a 25-year period. Neuropathologically, the 30 elderly cases presented features of several FTLD histological subgroups [FTLD-TDP (types 1, 2 and 3, 19 cases (63%)], FLTD-tau [MAPT, PiD and CBD, 10 cases (33%)] and FTLD-UPS (1 case), similar in range of phenotypes to that seen in the presenile group, though patients with MAPT, but not PGRN, mutation, or FUS pathology, were notably absent or fewer in the elderly group. Hippocampal sclerosis (HS) was present in 13/30 of the elderly FTLD cases (43%) compared with 14/79 (18%) (P = 0.012) in the presenile FTLD patients. Lobar atrophy present in most of the younger patients was prominent in only 25% of the elderly subjects. Prospective and retrospective psychiatric and medical case note analysis showed that the majority of the elderly FTLD patients, like their younger counterparts, had behavioural features consistent with frontotemporal dementia. FTLD is common amongst elderly persons and all or most of the major clinical and histological subtypes present in younger individuals can be seen in the older group.