MCCUNE-ALBRIGHT SYNDROME

McCune-Albright syndrome (MAS) is characterized by the clinical triad of polyostotic fibrous dysplasia, cafe-au-lait pigmented skin lesions, and multiple endocrinopathies. The molecular basis of MAS is a mutati on in G(s)alpha that results in constitutive activation of adenylyl cy clase in affected tissues. This mutation occurs during early embryogen esis, and therefore patients with MAS are mosaic. The identification o f activating mutations of G(s)alpha in liver, heart, and gastrointesti nal tract of patients with MAS suggests a broader spectrum of clinical disease than previously appreciated.