Paget disease of bone

Paget disease of bone is a disorder that causes unusual growth in one or more bones. Affected bones may be weakened, misshapen, and easily broken (fractured).

Paget disease of bone is typically diagnosed in middle age or later. The condition usually affects only one bone or just a few bones and does not spread from one bone to another. Any bones can be affected, although the disease most commonly affects bones in the spine, pelvis, skull, or legs.

Approximately 70 percent of people with Paget disease of bone do not experience any signs or symptoms related to the bone abnormalities. In these individuals, the disease is often diagnosed unexpectedly by x-rays or laboratory tests that are done for other reasons. Pain is the most common symptom reported by people with Paget disease of bone. The affected bones may themselves be painful, or pain may be caused by arthritis in nearby joints. Arthritis occurs when the abnormal bones, particularly weight-bearing bones in the legs, cause extra wear and tear on the joints. Arthritis in the knees and hips is common.

Other signs and symptoms of Paget disease of bone depend on the particular bones that are affected. If the disease affects the bones of the skull, affected individuals may have an enlarged head, hearing loss, headaches, and dizziness. When the condition affects bones in the spine(vertebrae), affected individuals may have an abnormal curvature of the spine or, less commonly, a narrowing of the spinal canal that can put pressure on the spinal cord (spinal stenosis). Spinal stenosis can lead to pain, tingling, and weakness in the legs. When the condition affects the leg bones, these bones may bow and fracture, which can interfere with the ability to walk. 

Some people with Paget disease of the bone have heart or kidney problems. Bone cancer (osteosarcoma) is a rare complication, affecting less than 1 percent of individuals with this condition.

A form of Paget disease that typically develops in childhood, known as juvenile Paget disease, tends to affect multiple bones and has a different pattern of inheritance than Paget disease of bone.