FAMILIAL GOITRE WITH PARTIAL IODINE ORGANIFICATION DEFECT, LACK OF THYROGLOBULIN, AND HIGH LEVELS OF THYROID PEROXIDASE

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Abstract
From a sibship of 3 sisters having congenital goiter and normal hearing, 2 had impairment of organification of iodide. S1 [subject 1] (4 yr old) had goiter since birth, euthyroidism and a negative perchlorate test. S2 (15 yr old) and S3 (13 yr 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 qualitatively normal but quantitatively increased. In the triiodide assay, the activity was: S1 6912 u [units], S2 2590 u and S3 3844 u (normal values 900-1700 u). In the tyrosine-iodinase assay, the activities, expressed as nmol of iodide incorporation per gram of tissue, were S1 1046, S2 471 and S3 547 (normal values 220-410). The activity of the thyroidal NADPH-cytochrome c reductase, an enzyme possibly involved in H2O2 generation, was: S1 0.084, S2 0.047 and S3 0.055 (normal values 0.018 .mu.eq/min per mg). No thyroglobulin was detected by analytical ultracentrifugation, polyacrylamide gel electrophoresis or double immunodiffusion in agar of the supernatant fractions. In patient S3, whose gland was labeled in vivo with 125I, 60% of the total radioactivity of the gland (pooled nodular and paranodular specimens) was in a particulate iodoprotein that was solubilized by trypsin, deoxycholate or digitonin. In the soluble fraction there were 2 iodoproteins: iodoalbumin and a 2nd iodoprotein similar to the solubilized particulate iodoprotein. Absence of the normal thyroidal receptor protein might be in some cases a cause of I organification defect.

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