Since the discovery of missense mutations in the fused-in-sarcoma (FUS) gene that are pathogenic for familial amyotrophic lateral sclerosis (ALS), a variety of clinically and pathologically diverse neurodegenerative diseases have been found to demonstrate FUS-positive inclusions in central nervous system (CNS) neurons [1-18]. The gene discussed is FUS; the disease is familial amyotrophic lateral sclerosis.