Accordingly, 95% of genetically defined SMA patients have deletions of exons 7 and/or 8 of SMN1 (SMN1Δ7, SMN1Δ(7–8)) that appear to be caused by Alu‐mediated rearrangements (Ottesen, Seo, Singh, & Singh, 2017). Here, SMN1 is linked to proximal spinal muscular atrophy.