RESUMEN
McCune-Albright syndrome (MAS) is a sporadic disease that's characterized by polyostotic fibrous dysplasia, cafe-au-lait pigmentation of the skin, and multiple endocrinopathies, including sexual precocity, hyperthyroidism, acromegaly, and hypercortisolism. Recent evidence has shown that the clinical manifestations are caused by a postzygotic activating missense mutation in the gene coding for the alpha-subunit of Gs protein that stimulates c-AMP formation in the affected tissues. Substitution of the Arg(201) residue in Gsalpha with cysteine or histidine have been identified in many MAS patients and Arg(201) to Gly or Leu mutations have also been recently identified. We identified the Arg(201) to His mutation in the gene encoding Gsalpha in the thyroid tissue from a 36-year-old man who was suffering with polyostotic fibrous dysplasia and hyperthyroidism.