Peptides and compositions for treatment of joint damage

A method of treating or ameliorating arthritis or articular cartilage damage in a subject, the method comprising administering to a joint of the subject a therapeutically effective amount of a polypeptide comprising an amino acid sequence that has at least 95% amino acid sequence identity to an amino acid sequence selected from the group of sequences of TABLE 1, wherein the polypeptide comprises an amino acid that is a polar amino acid other than K or R at position 423, as determined with reference to SEQ ID NO:1, and wherein the polypeptide has chondrogenic activity.