KHDRBS1 and proximal spinal muscular atrophy: Another splicing factor involved in neuronal functions is Sam68, encoded by the Khdrbs1 gene, which is highly expressed in brain and testis (Richard et al., 2005; Paronetto et al., 2009), and it was shown to be involved in the pathogenesis of fragile X tremor/ataxia syndrome (Sellier et al., 2010) and spinal muscular atrophy (Pedrotti et al., 2010; Pagliarini et al., 2015).