UBQLN2 and amyotrophic lateral sclerosis: Other genes linked to ALS/FTD include valosin-containing protein (VCP), a member of the AAA ATPase family with established function in the recycling and degradation of ubiquitinated proteins, and genes with functions in protein clearance or maintenance of protein homeostasis, including ubiquilin 2 (UBQLN2), vesicle-associated membrane protein–associated protein B, p62/sequestosome 1 (SQSTM1), optineurin (OPTN), and charged multivesicular body protein 2B (CHMP2B) (1, 29).