The patients described here have the heterozygous c.5C>G variant, a heterozygous deletion of exon 7, and two copies of SMN2, however, they exhibit a mild clinical course that is not consistent with patients with two copies of SMN2. This is highlighted by direct comparison to an SMA patient with homozygous deletion of exon 7 and two copies of SMN2 and a typical clinical course (Table 2). Here, SMN2 is linked to proximal spinal muscular atrophy.