You develop fibrous dysplasia before birth, and its development has been linked with a gene mutation that affects the cells that produce bone. No one knows what causes the mutation, but it isn't inherited from your parents, and you can't pass it on to your children.

Bones are living tissue, so even after you stop growing, your bones are in a continuous process of renewal known as remodeling. In the process, certain bone cells (osteoclasts) tear down (resorb) bone, while other cells (osteoblasts) rebuild bone. Fibrous dysplasia disrupts the process, causing old bone to break down faster and replacing normal bone tissue with softer, fibrous tissue.

Jul. 07, 2011