SMN2 and proximal spinal muscular atrophy: Being the leading monogenic cause of infant mortality [2], around 96% of SMA cases are mapped to homozygous loss-of-function and deletion mutations in the survival of motor neuron 1 (SMN1) gene [3, 4], which ubiquitously expresses SMN, a protein that current and ongoing research has linked to diverse housekeeping and tissue-specific cellular functions [5–7].