Apoptotic osteocytes (seen in disuse, glucocorticoid treatment, estrogen deficiency) induces osteoclast precursor recruitment and bone resorption.(41, 42) MM cells interact with osteocytes in the bone microenvironment and can promote MBD by increasing osteocyte apoptosis, increase sclerostin and RANKL production, and inhibit osteoblast differentiation. The gene discussed is SOST; the disease is Marchiafava-Bignami disease.