SMN2 and proximal spinal muscular atrophy: In addition, Hua et al. (2011) [35] demonstrated that systemic injection of a chemically modified antisense oligonucleotide specifically targeted to restore the aberrant skipping of exon 7 in the SMN2 gene profoundly ameliorated the viability and phenotypic features of mice affected by a severe form of Spinal Muscular Atrophy (SMA), a neurodegenerative disease [35].