Both DNAX activating protein of 12 kDa (DAP12) and Fc receptor common γ chain (FcRγ) contain cytoplasmic ITAM motif, and mice lacking DAP12 and FcRγ exhibit severe osteopetrosis due to the lack of osteoclasts [40, 41]. The gene discussed is FCER1G; the disease is osteopetrosis.