C9orf72 and amyotrophic lateral sclerosis: mRNA export factors SRSF1 and ALYREF have also been shown to directly interact with (G4C2) RNA foci using lysates from cell lines and C9orf72-ALS patient cerebellar tissue, as well as colocalizing with (G4C2) RNA foci in spinal motor neurons of C9orf72-ALS cases (Cooper-Knock et al., 2014; Hautbergue et al., 2017).