McCune-Albright syndrome is a disease that affects the bones, skin, and endocrine (hormone) system. It results from a mutation in a gene that occurs by chance in the womb. It is not inherited and passed down from one generation to the next.
People with McCune-Albright syndrome may have symptoms related to bones, the endocrine system, or skin. The symptoms can range from mild to severe. They include:
- Bone symptoms
- Polyostotic fibrous dysplasia – occurs when normal bone is replaced by softer, fibrous tissue. When this happens in weight-bearing bones, such as the leg bones, it can cause limping, deformity, and fractures.
- Dysplasia condition in the bones of the skull and upper jaw, making these bones grow unevenly. There is no known hormonal or medical treatment for controlling this aspect of disease, although surgery can help correct some fractures and deformities.
- Endocrine system symptoms
- Girls begin to show signs of puberty much younger than normal. Menstrual bleeding before two years of age is the first symptom for most female patients. Boys with the condition may show signs of puberty early, but these signs are less common than in girls.
- Thyroid function – The thyroid is a small gland in the neck that affects the metabolism. About half of patients have problems with their thyroid glands, such as enlargement or masses (called nodules or cysts). Drug therapy can sometimes improve thyroid function.
- Growth hormone – Some patients have too much pituitary growth hormone, which causes coarse facial features, larger hands and feet, and arthritis. Treatments include surgery and medication.
- Cushing’s syndrome – This is a rare problem for McCune-Albright syndrome patients. Symptoms include obesity of the face and body, weight gain, skin fragility, and stopping growth in childhood. Cushing’s syndrome is treated by removing the affected glands or with medicine.
- Skin symptoms
- Patches of increased or darker skin coloring, called café-au-lait spots. In children with light complexions, these spots are the color of coffee with milk. In darker skinned children, the spots might be hard to see. Most children have these spots from birth and the spots rarely grow. There are usually not any medical problems caused by these skin changes.
There is no cure for McCune-Albright syndrome. Drug treatments may help reduce or alleviate some of the symptoms, and surgery can help repair some of the bone problems.