Bone and joint involvement in adults with Werner's syndrome.

A 45-year-old man with Werner's syndrome had large asymptomatic calcium deposits about the elbows, hips, and shoulders. During the four-year follow-up, he developed insufficiency fractures of the pelvis, both ulnas, one radius and one metatarsal, all of which failed to heal. Bone mineral densities evaluated by dual-energy X-ray absorptiometry were at the lower end of the normal range, but a histomorphometric study showed a reduction in trabecular bone volume and marked decreases in osteoid parameters with a calcification rate of zero. Serum assays of 25 hydroxy vitamin D3, 1,25 dihydroxy vitamin D3, osteocalcin and alkaline phosphatase were normal. The nonunions in this patient may have been caused by impaired osteoblast function associated with Werner's syndrome and/or by decreased activity of growth factors involved in bone repair.