However, when Postn was downregulated in myoblast cells of both the normal and DM1 groups using shRNA and a neutralizing antibody, myogenesis and fusion markers (MyoD, MyoG, Mef2C, Mrf4, Myomaker, and Myomixer) displayed significant differences earlier than day 4. The gene discussed is POSTN; the disease is myotonic dystrophy type 1.