In this respect, an early study showed that the motor axon defects observed after silencing SMN and Gemin2 in zebrafish embryos could be rescued on injection of purified snRNPs [64] and recent work by Workman et al. [84] showed that restoring normal snRNP levels has a significant phenotypic rescuing effect on a severe SMA mouse model. This evidence concerns the gene SMN1 and proximal spinal muscular atrophy.