This article proposes the use of different cell-penetrating peptides (CPP) to produce a fusion protein that can be used as an enzyme replacement therapy, in order to treat bone abnormalities presented in Mucopolysaccharidosis 4A, caused by deficiency of N-acetylgalactosamine-6-sulfatase (GALNS) and the lysosomal accumulation of the glycosaminoglycans keratan sulfate and chondroitin 6-sulfate. The CPP chosen for this study are TAT, the Low Molecular Weight Protamine (LMWP) and PTD-5. TAT is the most studied and used CPP due to several characteristics such as its high arginine residues content, which gives it a high capacity for internalization, passive transport into the cell and the use of endocytic routes for cargo delivery to the lysosome. According to studies for osteogenesis improvement, it was found that LMWP has similar properties to TAT due to its ability of translocation into the cell. The main features of LMWP include the presence of two arginine clusters and the use of similar internalization routes as TAT. Finally, the PTDs are small cationic peptides that facilitate the entry of large molecules in different mammalian cells. It has been documented that PTD-5 has greater internalization capability in a wide variety of cells, including epithelial cells and chondrocytes, in comparison with its counterparts