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SUMMARY Two siblings, a brother (H. B.) and a sister (R. B.) with long standing goitres were investigated. Radioactive iodine uptake by the thyroid was increased and a significant portion of the plasma radioactive iodine was not extractable with butanol. Chromatography of butanol extracts of serum after radioactive iodine administration showed distinct peaks of triiodothyronine and thyroxine. Microscopic examination of the surgical specimens of the goitres showed Hürthle cell carcinoma with follicles devoid of colloid in both specimens. Sucrose density gradient centrifugation, gel filtration on Sephadex G-200, salting out procedures, starch gel electrophoresis and immunological tests of the supernatant soluble fraction of thyroid homogenates showed a lack of thyroglobulin. Further fractionation of the soluble proteins showed that albumin was apparently involved in the synthesis of thyroid hormones in the absence of thyroglobulin.

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Pendred's syndrome is characterized by familial goitre, nerve deafness and a partial release of radio-iodine from the thyroid on perchlorate administration. This last was thought to be due to impaired activity of peroxidase enzymes or to some abnormality of receptor proteins where iodination occurs. Burrow, Spaulding, Alexander & Bower (1973) reported that peroxidase activity in such patients is normal but studies on thyroidal iodoproteins have shown variable results (MedeirosNeto, Nicolau, Kieffer & Ulhoa-Cintra, 1968;Milutinovic et al. 1969).A 22-year-old deaf-mute woman (N.G.) with a goitre which had progressively increased in size from infancy was euthyroid in all respects: basal metabolic rate, 10-0%; serum cholesterol concn, 174-3 mg/100 ml; tri-iodothyronine (T3) red blood cell uptake, 14-6%; stable protein-bound iodine levels, 5-7/tg/100 ml. Radioactive iodine uptake by the thyroid was 65-7 % at 2 h, 73-2 % at 24 h and 73-5 % at 48 h. Administration of 1-0 g perchlorate 2 h after an oral dose of 131I released 22-0% of accumulated radioactivity within 2-5 h. A 48 h thyroid scan showed an enlarged gland with multiple unlabelled areas. The patient's brother and 2-year-old daughter were deaf, dumb and goitrous from childhood; her sister was normal.Eight days before operation, 500 /tCi Na125I were administered orally. Butanolextractable iodine was normal 24 h afterwards ; T3 and thyroxine (T4) were detectable in serum by chromatography using butanol : acetic acid: water (I) and butanol: ethanol : ammonia (II) systems. No abnormality was seen in chromatograms of serum and urine. The microscopic appearance of a surgical specimen was that of a non-toxic nodular goitre. Results obtained from tissue taken from an area showing maximum concentration of label and from an unlabelled area were identical.The tissue was homogenized in sucrose-Tris-magnesium buffer (pH 7-4), and separated into subcellular fractions. A tryptic digest of the supernatant fraction (105000 g) was examined by paper chromatography using systems I and II (see above). Soluble proteins in the supernatant fraction were studied by column chro¬ matography on Sephadex G-200, salting out procedures, starch gel electrophoresis and immunological reactions. For methods see Desai, Mehta, Patel, Sharma, Ramanna & Ganatra (1974). Sedimentation co-efficients of soluble proteins were determined by the method of Schachman (1957).The proportion of 125I in nuclear, mitochondrial and microsomal fractions was 0-8%, 1-0% and 1-4%, respectively and the remainder was in the supernatant