CSF1 and osteopetrosis: The severe osteopetrosis, shortened long bones and failure of dental eruption in Csf1op/ Csf1op mice attest to the essential role of M-CSF for osteoclast generation (Cecchini et al., 1994; Dai et al., 2002; Felix et al., 1990; Wiktor-Jedrzejczak et al., 1982; Wiktor-Jedrzejczak et al., 1990; Yoshida et al., 1990).