Fibrodysplasia Ossificans Progressiva

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder that causes soft tissues to transform permanently into bone. These bones grow abnormally in the muscles, tendons, ligaments and other connective tissues, forming bridges of extra bone across the joints. As a result, movement in the areas affected by FOP are greatly restricted and sometimes impossible.

FOP affects many areas of the body including, but not limited to, the neck, spine, chest, shoulders, elbows, wrists, hips, knees, ankles and jaw. It is an autosomal dominant condition, which means that a person needs only one gene for FOP to inherit the disease.

In most cases, FOP is a new mutation or an accident of nature. In fact, the parents of FOP patients typically don't have the disease. A person with FOP, however, has a 50 percent chance of passing it on to a child.

Worldwide, FOP affects only about 2,500 people, or one in 2 million, of all ethnicities, ages and races. Because FOP is such a rare disease, experts believe that 80 percent or more of the cases are misdiagnosed and its prevalence may be much higher than known.

Experts in both pediatric and adult orthopedics, orthopedic surgery and rheumatology at UCSF Children's Hospital are among the few in the country who readily diagnose and treat FOP. In addition, researchers at UCSF are investigating the rate of misdiagnosis of FOP and the most common causes for misdiagnosis.

For information about treatment for fibrodysplasia ossificans progressiva (FOP) at UCSF Children's Hospital, please call (415) 476-7242.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated May 8, 2007