Another causative gene associated with ALS is Sigma receptor 1 (SIGMAR1, SigR1), a ligand-activated chaperone protein (improperly defined as a “receptor“, as it was mistaken for an opioid receptor) that resides in the mitochondrion-associated endoplasmic reticulum membrane (MAM) of the cell [20,21]. The gene discussed is SIGMAR1; the disease is amyotrophic lateral sclerosis.