Several studies in animal models of SMA have investigated the inhibition of myostatin as a potential therapeutic target, often utilizing follistatin or follistatin analogues.40,43,49-53 Initial studies using recombinant follistatin administration in the SMN Delta7 mouse model demonstrated increased muscle mass, improved motor performance, and extended survival, regardless of SMN levels. This evidence concerns the gene SMN2 and proximal spinal muscular atrophy.