2′-F-modified ASO10-27 inhibits SMN2 splicing, due to recruitment of IFL2 and IFL3 near the 5′ splice site of intron 7 by the 2′-F/RNA duplex (54), resulting in exon 7 skipping, and therefore, this modification cannot be used to treat SMA. This evidence concerns the gene SMN2 and proximal spinal muscular atrophy.