HIV-infected men who had lost in excess of 10% of their premorbid weight and were considered to have acquired immunodeficiency syndrome (AIDS) also had higher serum myostatin levels than HIV-infected men without AIDS, suggesting that increased intramuscular myostatin production contributes to the AIDS-associated muscle wasting syndrome (Gonzalez-Cadavid et al., 1998). Here, MSTN is linked to AIDS.