The first five nucleotides of ISS-N1 also overlaps with an upstream 8-nucleotide-long GC-rich motif, sequestration of which by a short ASO promoted SMN2 exon 7 inclusion and provided therapeutic benefits in mouse models of SMA (Singh et al., 2009; Keil et al., 2014). This evidence concerns the gene SMN2 and proximal spinal muscular atrophy.