With increasing days in culture, cardiomyocytes upregulate genes associated with structure, function and metabolism, including genes such as Myosin light chain 7 (Myl7), Myosin heavy chain 6 (Myh6) and Ryanodine receptor 2 (Ryr2). Downregulation of progenitor genes such as Isl1 and Myocyte-specific enhancer factor 2C (Mef2c) is also observed, highlighting the progressive maturation of CCO cardiomyocytes in culture [98]. This evidence concerns the gene MEF2C and central core myopathy.