RAG2 and osteoarthritis: The early onset osteoarthritis condition observed in Mig6 knockout mice (Zhang et al. 2005) suggested the possibility that inflammatory conditions may be driven by Mig6 deficiency and be involved in the development of the joint disease and the minor increase in vascular leakage in the absence of external stimuli; however, no significant infiltration of inflammatory cells was observed in the diseased joints of the mice and further ablation of Rag2 gene did not rescue the joint phenotype of the Mig6-deficient mice (Zhang et al. 2005).