The role of NF-κB in OC differentiation was discovered in the late 1990s when NF-κB1−/− mice were crossed with NF-κB2−/− mice to generate NF-κB1/2 double knockout (dKO) mice that developed severe osteopetrosis due to an OC defect [121,122]. Here, NFKB1 is linked to osteopetrosis.