Amyotrophic lateral sclerosis (ALS) and certain forms of frontotemporal lobar degeneration (FTLD) with ubiquitin-positive but tau-negative inclusions have been considered to be a single disease spectrum of TAR DNA-binding protein 43 (TDP-43) proteinopathy since 2006, when this protein was reported to be a major component of ubiquitin-positive inclusions in the affected neuronal and glial cells of both ALS and FTLD [1]–[3]. The gene discussed is MAPT; the disease is amyotrophic lateral sclerosis.