Encouraging data come from two studies in which administration of Plastin-3 (PLS3) or suppression of neurocalcin delta (NCALD) failed to modify the severe SMA phenotype, while combining these strategies with an SMN protein increasing compound had additional benefit (Kaifer et al., 2017; Riessland et al., 2017). Here, SMN1 is linked to proximal spinal muscular atrophy.