ERBB4 and amyotrophic lateral sclerosis: Maltese ALS patients nevertheless possessed deleterious alleles in ‘minor’ ALS genes including ALS2, ATXN2, DAO, DCTN1, ERBB4, NIPA1, SETX, SCFD1 and SPG11. ALS2 and SPG11 have been associated with juvenile-onset ALS only under a recessive disease model [55–58].