CTSB and muscular dystrophy: For example, E64 and their family derivatives are potent inhibitors of cysteine proteases (cathepsin B, H, L, and calpain), reducing muscular dystrophy, improving locomotor activity, protecting proteoglycan degradation, preventing lesion and apoptosis, attenuating parathyroid hormonal effect on calpain, preventing viral replication and coronavirus protein processing and other biological effects; however, it is associated with hepatic injury, teratogenesis, and attenuated myofibril assembly [99].