The transactivation response element DNA-binding protein 43 kDa (TDP-43) is a major component of the ubiquitin-positive and tau-negative inclusions in frontotemporal lobar degeneration (FTLD-TDP) and sporadic amyotrophic lateral sclerosis (ALS) [1–3]. The gene discussed is MAPT; the disease is sporadic amyotrophic lateral sclerosis.