Out of the 72 targets identified by arginine methyl proteome profiling of human cells (Fong et al, 2019), MS023 changed the methylation pattern of other splicing factors implicated in the regulation of SMN2 splicing (i.e. HNRNPU, HNRNPA2B1, ELAVL1, RBM10, KHDRBS1, SRSF9, TRA2B, and U2AF1; Singh & Singh, 2018), and the individual contribution of such proteins to the overall effect of this small molecule in SMA models remains to be established. The gene discussed is SMN2; the disease is proximal spinal muscular atrophy.