Abstract
Abnormal intracellular accumulation of the fused in sarcoma (FUS) protein is the characteristic pathological feature of cases of familial amyotrophic lateral sclerosis (ALS) caused by FUS mutations (ALS-FUS) and several uncommon disorders that may present with sporadic frontotemporal dementia (FTLD-FUS). Although these findings provide further support for the concept that ALS and FTD are closely related clinical syndromes with an overlapping molecular basis, important differences in the pathological features and results from experimental models indicate that ALS-FUS and FTLD-FUS have distinct pathogenic mechanisms.