Studies have shown that in patients with severe COPD, the cross-sectional area of all types of muscle fibers is reduced by 40–60% compared with non-COPD controls and that apoptosis and atrophy of the diaphragm induced by myostatin overexpression can lead to diaphragm weakness and respiratory muscle dysfunction (Levine et al., 1997; Zhou et al., 2018). Here, MSTN is linked to chronic obstructive pulmonary disease.