Mutations in the UBQLN2 gene encoding the ubiquitin-like protein ubiquilin 2 cause X-linked ALS/FTLD, and UBQLN2-positive inclusions are identified in ALS with UBQLN2 mutations as well as in cases of both familial and sporadic ALS without UBQLN2 mutations [144]. This evidence concerns the gene UBQLN2 and amyotrophic lateral sclerosis.