Four proteins that are abundant in skeletal muscle tissue, that is, myofibrillar proteins skeletal troponin I (sTnI), myosin light chain 3 (MYL3), fatty acid binding protein 3 (FABP3), and creatine kinase muscle-type (CKM), were determined to be significantly elevated in serum of both DMD and BMD patients and correlated with certain clinical endpoints in DMD patients, such as forced vital capacity.42 This evidence concerns the gene CKM and Becker muscular dystrophy.