SMN2 and spinal muscular atrophy: Exon 7 skipping of survival motor neuron 2 (SMN2) pre-mRNA, a key gene in patients with spinal muscular atrophy (SMA), led to abnormal growth of motor neurons, whereas targeting 2 ISSs (UAGGGU and UAGGUC) in the proximal intron region of exon 7 flanks promoted the inclusion of exon 7 of SMN2 by inhibiting hnRNPA1/A2-mediated splicing, highlighting the therapeutic potential of ISS in diseases.