The first set of symptoms is if a patient has already been diagnosed with fibrous dysplasia. The same gene mutation causes both fibrous dysplasia and McCune-Albright syndrome, although not all people with fibrous dysplasia have McCune-Albright syndrome. This close tie between fibrous dysplasia and McCune-Albright syndrome is why the disorder is often referred to as FD/MAS and why our organization bears the same name.
Additionally, the skin of individuals with McCune-Albright syndrome may have areas of increased skin pigment, often called café-au-lait macules. The term “café-au-lait,” however, refers to the color of the lesions in light-skinned individuals, which resembles the color of coffee with milk. In dark-skinned individuals, the lesions may be more challenging to see. The pigment distribution pattern is distinctive, often starting or ending abruptly at the midline of the body. The borders tend to be jagged and irregular. The macules are usually present at birth and do not change significantly over a patient’s lifetime.
Finally, many people with McCune-Albright syndrome may also have hyperfunctioning endocrine disease. This can lead to many other issues or symptoms, such as:
- Early or precocious puberty – This is most common in girls and women, occurring in about 85% of cases
- Testicular abnormalities – Seen in the majority of cases of boys and men, occurring in about 85% of cases
- Overproduction of thyroid hormones (hyperthyroidism) – Occurs in about ⅓ of MAS patients
- Excessive growth hormone production – Found in about 15% of patients
- Cushing’s disease (excess production of cortisol) – This is very rare McCune-Albright syndrome symptom
- Hypophosphatemia (low blood phosphate levels) – This can lead to rickets and osteomalacia