In line with findings by Watihayati et al. [10], among patients with type I SMA, 71% carried two SMN2 gene copies and 29% carried one, whereas in milder phenotypes (types II and III), 71% had three or more copies—specifically, 29% with two, 57% with three, and 14% with four copies—highlighting the inverse correlation between SMN2 copy number and disease severity [10]. The gene discussed is SMN2; the disease is proximal spinal muscular atrophy.