Fibrous Dysplasia

Dr. Greene's Answer

I commend your desire to become an expert on fibrous dysplasia. Since our health is so central to our entire experience of life, becoming knowledgeable about our health is of great practical value. All of us would do well to be at least somewhat informed about nutrition, exercise, and safety measures that work against the major threats to our well-being. Mothers and fathers benefit from learning about parenting and about child development. Each of us stands in a better position if we are informed about our own particular health problems.

Fibrous dysplasia is the most common bone abnormality that occurs during the years of growth and development (as opposed to osteoporosis, the most common bone abnormality during the years of our bodies’ decline). Dysplasia means abnormal development. Fibrous dysplasia is a disease of the bone in which the outer layers of the bone become thin, and the inner bone marrow is replaced by a gritty fibrous tissue containing sharp, needle-like fragments of bone.

Fibrous dysplasia is usually first apparent in late childhood. It can occur in only one bone (monostotic) or in several or many bones (polyostotic). Monostotic fibrous dysplasia is up to six times as common as the polyostotic form (Orthopedics, August 1996). In polyostotic fibrous dysplasia, up to 75% of the skeleton may be involved. Often fibrous dysplasia is discovered when a bone fractures from relatively minor trauma. Unfortunately, fractures through dysplastic bone do not heal well until the fibrous tissue is surgically removed.

For many with fibrous dysplasia, the bony spicules in the marrow cause bone pain, disability, and slowly progressing deformity. It acts like a benign bone tumor that usually continues to grow until the adolescent growth spurt is completed. Once full growth is achieved, the progression of the disease often stops, but people are left with one or more weakened areas of bone. These are sometimes removed surgically, depending on their extent.

When it occurs in the jaw, the swelling of the angle of the jaw (sometimes accompanied by upturned eyes from facial fibrous dysplasia), gives a cherubic look to the face. In fact, fibrous dysplasia of the jaw has its own name — cherubism.

Research has linked fibrous dysplasia to genetic mutations causing increased activity of a protein called G alpha s protein. Researchers believe that the mutation causes increased activity of bone dissolving cells. Bisphosphonates are a class of drugs which may work by inhibiting bone breakdown and have been shown to improve the symptoms. Some patients will require surgical interventions such as the implantation of healthy bone, steel, or titanium to strengthen weakened areas affected by fibrous dysplasia.

As you well know, the current treatment options are rather crude and after the fact. To me, the most exciting breakthroughs will be in discovering medicines that cure the disease at the root – perhaps by turning off the gene that is responsible for the disease. And who knows, you may be the champion who leads the way to these thrilling discoveries!