1. Thyroid Study Unit (LIM-25) (V.P., J.V.-T., I.G.S.R., M.K., R.F.P., G.M.-N.), Division of Endocrinology, University of São Paulo Medical School, São Paulo 05311-970, Brazil
2. Laboratorio de Biología Molecular (H.M.T.), Cátedra de Genética y Biología Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1113 Buenos Aires, Argentina
3. Division of Endocrinology, Metabolism and Molecular Medicine (P.K.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611