The appearance of a fingerprint pattern in pagetic osteoclastic nuclei on electron microscopy of involved bone suggests a viral infection. Paget's disease sometimes is familial, but a specific genetic pattern is unclear. The disease is more common in Eastern and Western Europe, England, Australia, and New Zealand. Pathophysiology Bone turnover is hyperactive at involved sites. Excessively active osteoclasts are often large and contain many nuclei.
Osteoblastic repair is also hyperactive, producing coarsely woven thickened lamellae and trabeculae.
The mosaic layering of collagen results in structurally enlarged and weakened bone, although heavily calcified. Abnormal remodeling with change in the shape of bone may cause nerve compression. Osteoarthritis may develop in joints contiguous to pagetic bone. The disorder usually is asymptomatic. Onset of symptoms is usually insidious, with pain, stiffness, fatigability, bone deformity, headaches, decreasing auditory acuity, and increasing skull size.