MAS symptoms can vary from mild to severe. They may begin at birth or later in childhood.1
Main Symptoms
Many people with MAS have the following symptoms:
- Café-au-lait spots
Café-au-lait (French for "coffee with milk") spots, which are light-brown birthmarks. The birthmarks2,3:- Are usually are present at birth
- May be hard to see on dark skin
- Often appear on one side of the body
- Have jagged edges sometimes referred to as the "coast of Maine"
- Polyostotic fibrous dysplasia2,3
A person with polyostotic fibrous dysplasia (PFD) has scar-like tissue, or fibrous tissue, in his or her bones. PFD usually occurs on one side of the body in weight-bearing bones, such as leg bones. PFD may cause:- Bone pain
- Cancer of the bone (very rare)
- Abnormal bone growth
- Fractures
- Limping
- Scoliosis a curvature of the spine
- Uneven growth, including uneven growth of the face
In addition, bone lesions in the skull may pinch nerves that affect a person’s ability to see and hear.3
- Precocious puberty2,3,4
Precocious puberty is when sexual and physical changes occur earlier than normal.
Girls with MAS may experience such symptoms as:- Early menstrual bleeding, usually before 2 years of age
- Early breast growth
- Beginning to grow faster
- Faster than normal growth of penis or testicles
- Premature sexual behavior
- Early growth of armpit or pubic hair
Additional Symptoms
Additional features of MAS may include (but are not limited to)1,2,3,6:
- Overproduction of growth hormone from the pituitary gland
- Cushing syndrome, overactivity of the adrenal glands, leading to an increase in stress hormone levels
- Formation of benign (noncancerous) tumors in the testicles, called Sertoli cell hyperplasia and Leydig cell hyperplasia
- Hyperthyroidism, an overactive thyroid gland
- Loss of phosphate in the urine, leading to low blood phosphorus levels
- Liver disease