The etiology of Paget's disease of bone.

The etiology of Paget's disease is not known but recent studies of the ultrastructure of bone cells in pagetic lesions have raised the possibility of a viral etiology. In 41 of 41 patients evaluated in France and Los Angeles characteristic nuclear inclusions were found in osteoclasts only. These structures were similar to nuclear inclusions found in the slow virus infection of the brain, subacute sclerosing panencephalitis. Definitive identification of a virus or viral antigens in pagetic lesions awaits future studies. Other possible etiologies of Paget's disease include an inborn error of connective tissue biosynthesis, a disorder of hormone secretion, a vascular disorder, an autoimmune state, and a neoplastic transformation of bone cells.