MSTN and X-linked myotubular myopathy: However, the inhibition of the myostatin/activin A pathway can also reverse muscle loss in other diseases such as Duchenne muscular dystrophy [89,90,91,92], metabolic diseases (obesity and diabetes) [93,94], androgen deficiency [95], X-linked myotubular myopathy [96], amyotrophic lateral sclerosis [97], and limb-girdle muscular dystrophy [98].