MSTN and proximal spinal muscular atrophy: Given its pivotal role in negatively regulating muscle development, myostatin has become a compelling target of research in the context of Spinal Muscular Atrophy (SMA)—a severe, genetically inherited neuromuscular disorder characterized by progressive degeneration of α-motor neurons in the anterior horn of the spinal cord, leading to denervation-induced skeletal muscle atrophy, weakness, and, in severe cases, paralysis [19,20].