GNAS and Cafe-au-lait spot: McCune-Albright syndrome results from somatic activating mutations in the GNAS gene and is characterized by polyostotic fibrous dysplasia, café-au-lait spots, and endocrine hyperfunction; approximately 5% of affected patients develop cortisol-secreting adrenal lesions, often presenting as macronodular adrenal hyperplasia [9,11].