Spinal muscular atrophy (SMA) is a rare but severe neurogenetic disorder primarily caused by loss of or mutation in the survival motor neuron 1 (SMN1) gene on chromosome 5q13, which leads to degeneration of α-motor neurons with resulting muscular atrophy and impairment of motor neuron function [1]. The gene discussed is SMN1; the disease is proximal spinal muscular atrophy.