Abstract: The disruption of the murine ROR2 gene leads to profound skeletal abnormalities, with essentially all endochondrally derived bones foreshortened and/or misshapen, albeit to differing degrees. ROR2 is selectively expressed in the chondrocytes of all developing cartilage anlagen, where it plays a critical role during initial growth and patterning, as well as subsequently in the proliferating chondrocytes of mature growth plates, where it is required for normal expansion. As ROR2 appears to play a critical role in cartilage formation and it may be useful in developing therapeutic strategies to treat diseases of cartilage such as osteoarthritis.