Among the 11 Type I SMA children, there was no patient with a complex gene deletion of NAIP or GTF2H2. The survival rates between Type I SMA patients with a homozygous deletion of NAIP or GTF2H2 and patients without a deletion in NAIP or GTF2H2 were analysed (Fig. 4a). Here, NAIP is linked to proximal spinal muscular atrophy.