MSTN and heart disorder: Despite emerging myostatin-blocking drugs, myostatin alone is apparently not classified by guidelines as a therapeutic target for muscle diseases in the same manner as low-density lipoprotein-cholesterol for hypercholesterolemia and related heart diseases, blood pressure for hypertension, fasting blood glucose for diabetes, or blood total testosterone for male hypogonadism [12,13,14,15,16,17,18].