McCune Albright Syndrome eMedicine

Description: Author: Gabriel I Uwaifo, MBBS, Clinical and Research Attending, MedStar Clinical Research Center, Assistant Professor of Medicine and Endocrinology, The MedStar Research Institute and the Washington Hospital Center Coauthor(s): Nicholas J Sarlis, MBBS, MD, PhD, FACP, Medical Director, Department of Oncology-US Medical Affairs Department, Sanofi-Aventis Pharmaceuticals Background McCune-Albright syndrome (MAS) is defined as the association of polyostotic fibrous dysplasia (PFD) (see Image 1), precocious puberty, café au lait spots, and other endocrinopathies due to hyperactivity of various endocrine glands. Fuller Albright first described this syndrome in 1937. The first case described by Donovan McCune had the classic triad and hyperthyroidism. Other cases have been retrospectively identified since antiquity, such as the Tegernsee Giant, who probably had MAS and acromegaly. MAS has been shown to be due to a postzygotic activating mutation of the GS alpha gene in the affected tissues. For semantic reasons, differentiating MAS and Albright hereditary osteodystrophy (AHO) is important. AHO also is a GS alpha gene defect that results in pseudohypoparathyroidism or pseudopseudohypoparathyroidism. The precocious puberty associated with MAS typically is gonadotrophin-independent. Among the endocrine syndromes described in association with MAS are (1) hyperthyroidism, (2) acromegaly, (3) gonadotrophinomas, (4) hyperprolactinemia, (5) Cushing syndrome, (6) hyperparathyroidism, (7) gynecomastia, and (8) hypophosphatemic rickets. Some severely affected patients may present with associated hepatic, cardiac, and GI dysfunction (ie, elevated hepatic transaminases, GI polyposis, and cardiomyopathy).