Paget's disease of bone.

The highest incidence of Paget's disease is in the United Kingdom and is lower in other European countries. Worldwide the incidence appears to be decreasing. Some countries have observed a reduction in the severity at presentation, perhaps reflecting changes in migration of the UK population. Evidence of a genetic susceptibility to Paget's disease is accumulating, with chromosome 6 (the HLA locus) and 18q emerging as strong candidates. Use of molecular biology techniques has yielded evidence on the possible role of paramyxovirus infection in the etiology of Paget's disease. Altered measles virus nucleocapsid transcripts have been detected in bone marrow cell cultures and peripheral blood mononuclear cells from Paget's disease patients. Canine distemper virus may be the etiologic agent, and ownership of a mongrel dog or a dog not vaccinated against canine distemper virus is associated with an increased risk of Paget's disease. Familial Paget's disease is associated with more severe disease than is seen in sporadic cases. Quality of life may be reduced in patients with Paget's disease, and psychological problems are often present. New biochemical markers of resorption and formation appear to offer little advantage over urinary hydroxyproline and serum total alkaline phosphatase measurements in assessing Paget's disease activity or response to therapy. The best therapeutic responses are observed following treatment with the bisphosphonates, and oral etidronate is now being superseded by oral tiludronate, oral or intravenous alendronate, and clodronate or intravenous pamidronate.