Our in vivo work was conducted in both vertebrate and invertebrate models of SMA, which led to several key observations such as the ability of mifepristone to improve the survival of Smn2B/- mice as well as improve neuromuscular pathology in both Smn2B/- mice and C. elegans smn-1(ok355) models. This evidence concerns the gene SMN1 and proximal spinal muscular atrophy.