[Quantitative aspects of iodine metabolism in one case of congenital iodotyrosine deiodinase defect (author's transl)].

In a 27 years old patient an iodotyrosine deiodinase defect was responsible for a profound hypothyroidism (T4-RIA: indetectable -- TSH: 190 microU/ml) associated with a large goiter (about 300 g). MIT and DIT secretions were measured from the urinary cumulative specific activities, and the molar MIT/DIT ratio was 2.2. The thyroidal iodine exchangeable pool was as low as 177 micrograms. In two comparable patients rendered euthyroid by Lipodol injection, total thyroidal 127I pool was around 40 mg and the MIT/DIT ratio was degraded to 7 suggesting a mild biosynthetic defect by iodine excess.