SMN2 and proximal spinal muscular atrophy: For drug discovery for SMA, several small molecules including sodium vanadate [69], aclarubicin [70], and indoprofen [71], hydroxyurea [72], valproate [73], 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) [74], and phenylbutyrate [75] that increases inclusion of exon 7 of SMN2 gene have been identified, although some of them may have side effects.