C9orf72 and amyotrophic lateral sclerosis: Neural progenitor cells derived from an ALS patient with a TARDBP mutation differentiate in vitro to mature oligodendrocyte as efficiently as cells derived from non-ALS cases or other sALS and fALS patients, including those with C9orf72 mutation, whereas mutant FUS carriers were not investigated (Ferraiuolo et al., 2016; Livesey et al., 2016).