UBQLN2 and amyotrophic lateral sclerosis: Interestingly, a causal role for proteasomal dysfunction is emerging more widely from other neurodegenerative disorders through the identification of X-linked mutations in Ubiquilin2 (UBQLN2) in amyotrophic lateral sclerosis and the demonstration that UBQLN2 plays a crucial role as a proteasome shuttle factor clearing aggregates via the proteasome [15].