The present invention relates to a GDF-5-related protein that improves the ability to induce cartilage formation and reduces the ability to induce bone formation. The novel proteins described above are particularly useful for the treatment of cartilage defects where bone tissue formation is undesirable. [Selection] Figure 3【課題】本発明は、軟骨形成の誘導能を向上し、硬骨形成の誘導能を低減させるGDF-5関連タンパク質に関する。【解決手段】上記の新規タンパク質は、硬骨組織の形成が望ましくない、軟骨欠陥の治療に特に有用である。【選択図】図3