APOE and amyotrophic lateral sclerosis: The possible existence of a common genetic background in neurodegeneration is also supported by the observation that mutations in ATXN2, SPAST, FIG4, SETX, DCTN1, MATR3, CHCHD10, SQSTM1, VAPB, HNRNPA1, VCP, APOE, and OPTN have been reported both ALS and other multisystem disorders, including FTD, spinocerebellar ataxias, parkinsonism and schizophrenia.