NFKB1 and osteopetrosis: While Caron et al. (2012) showed that RelA/p65 mediated signaling facilitates chondrogenic differentiation, a study by Franzoso et al. (1997) demonstrated that the simultaneous knockout of the RelA and RelB binding partners p50 and p52 resulted in impaired osteogenic differentiation causing osteopetrosis in mice.