Osteoporosis is a chronic systemic disease characterized by progressive loss of bone mass and microarchitectural deterioration of bone tissue. Bone lesions are caused by different factors, including hereditary ones. A process named bone remodeling is the effect of balanced osteoclastogenesis and oste- oblastogenesis, two primary processes controlled by a number of proteins. The osteoclasts proliferation and differentiation are regulated by: PU.1, MITF, M-CSF, c-Src, PI-3K, c-Fms, RANK, NFATc1, NFκB and cFos/Fra-1 proteins.