Familial goitre with partial iodine organification defect, lack of thyroglobulin, and high levels of thyroid peroxidase.
From a sibship of three sisters having congenital goitre and normal hearing, two had impairment of organification of iodine. S1 (4 years old) had goitre since birth, euthyroidism, and a negative perchlorate test. S2 (15 years old) and S3 (13 years old) were hypothyroid, and had radioiodide discharge after potassium perchlorate administration of 19.8% and 26.1%, respectively. Thyroid tissue was obtained at thyroidectomy. Peroxidase activity, in the thyroidal subcellular particles, was found to be qualitatively normal, but quantitatively increased. In the triiodide assay, the activity was: S1 6912 u, S2 2590 u, and S3 3844 u (normal values 900-1700 u). In the tyrosine-iodinase assay, the activities, expressed as nmoles of iodide incorporation per gram of tissue, were S1 1046, S2 471 (normal values 220-410). The activity of the thyroidal NADPH-cytochrome c reductase, an enzyme possibly involved in hydrogen peroxide generation, was: S1 0.084, S2 0.047, and S3 0.005 (normal values 0.018 muEq/min/mg). No thyroglobulin was detected by analytical ultracentrifugation, polyacrylamide gel electrophoresis, or double immunodiffusion in agar of the supernatant fractions. In patient S2, whose gland was labelled in vivo with 125I, 60% of the total radioactivity of the gland (pooled nodular and paranodular specimens) was in a particulate iodoprotein that was solublilized by trypsin, deoxycholate or digitonin. In the soluble fraction there were two iodoproteins: iodalbumin, and a second iodoprotein similar to the solubilized particulate iodoprotein. It is postulated that absence of the normal thyroidal receptor protein might be in some cases a cause of iodine organification defect.
D000293:Adolescent; D002675:Child, Preschool; D005260:Female; D006042:Goiter / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007453:Iodide Peroxidase / Q000378:metabolism; D007455:Iodine / Q000378:metabolism*; D010375:Pedigree; D013954:Thyroglobulin / Q000378:metabolism*; D013961:Thyroid Gland / Q000201:enzymology / Q000378:metabolism*
D013954:Thyroglobulin; D007455:Iodine; D007453:Iodide Peroxidase