SMN1 and proximal spinal muscular atrophy: In the last decade, significant improvements have been made in SMA treatment, resulting in three available therapies, namely the SMN2 splicing-modifiers nusinersen (antisense oligonucleotide administered intrathecally) and risdiplam (small molecule with oral route), which upregulate SMN protein levels [5, 6], and onasemnogene abeparvovec (an adeno-associated virus vector-based gene therapy administered once i.v.)[7].