The most common form of SMA results from a defect in the survival motor neuron 1 (SMN1) gene located on 5q11.2-q13.3, also called 5q-SMA with an incidence of approximately 1:10,000 among newborns and a carrier frequency of 1:50 worldwide (Eggermann et al., 2020). The gene discussed is SMN1; the disease is proximal spinal muscular atrophy.