MYH7 and polycystic ovary syndrome: Several proteins that are more highly expressed in type I muscle fibers consistently had a lower expression in women with PCOS, e.g., myosin heavy chain 7, myosin regulatory light chains 2 and 3, troponin I and troponin T in slow skeletal muscle, and the Ca2+ pump sarcoendoplasmic reticulum calcium ATPase 2 (SERCA2a).