A recent study on old mice (26 months old) suggested that increased expression of local skeletal muscle IGF-1 isoforms (IGF-1 Ea and IGF-1 Eb) counteracted sarcopenia, which included increased SIRT1 muscle content, autophagy and PGC-1α, without inducing any negative effects in other tissues compared to wild type mice (80). The gene discussed is IGF1; the disease is sarcopenia.