The thyrotropin receptor (TSHR), a member of the large family of G protein-coupled receptors, controls both the function and growth of thyroid cells via stimulation of adenylyl cyclase. We report two different mutations in the TSHR gene of affected members of two large pedigrees with non-autoimmune autosomal dominant hyperthyroidism (toxic thyroid hyperplasia), that involve residues in the third (Val509Ala) and seventh (Cys672Tyr) transmembrane segments. When expressed by transfection in COS-7 cells, the mutated receptors display a higher constitutive activation of adenylyl cyclase than wild type. This new disease entity is the germline counterpart of hyperfunctioning thyroid adenomas, in which different somatic mutations with similar functional characteristics have been demonstrated.

Angiogenesis is implicated in several pathological conditions, such as inflammation and tumor growth.

Vascular endothelial growth factor (VEGF) is a potent stimulator of endothelial cell proliferation. It has been implicated in tumor growth of human thyroid carcinomas. Using the VEGF immunohistochemistry staining score, we correlated the level of VEGF expression with the metastatic spread of 19 cases of thyroid papillary carcinoma. The VEGF immunostaining score, ranging from 0-9, was determined as the multiplication of a percentage of labeled thyrocytes score (0, no labeling; 1, <30%; 2, 31--60%; 3, >61% of labeled thyrocytes) and an intensity score (0, no staining; 1, weak; 2, mild; 3, strong staining). The mean score +/- SD was 5.74 +/- 2.59 for all carcinomas. The mean score for metastatic papillary carcinoma was 8.25 +/- 1.13 vs. 3.91 +/- 1.5 for nonmetastatic papillary cancers (P < 0.001). By discriminant analysis, we found a threshold value of 6.0, with a sensitivity of 100% and a specificity of 87.5%. There were no statistical differences between metastatic and nonmetastatic carcinomas when age, tumor size, or thyroglobulin levels were considered. The VEGF immunostaining score seems to be a helpful marker for metastasis spread in differentiated thyroid cancers. An increased production of VEGF could assess an aggressive disease and be the hallmark of a trend to produce metastasis. We propose the VEGF immunostaining score as a marker for the prognosis in differentiated thyroid cancers. A value of 6 or more, should be considered as at high risk for metastasis threat, prompting the physician to institute a tight follow up of the patient.

Three syndromes affecting the thyroid gland are described in the literature separately: familial nonautoimmune hyperthyroidism, sporadic congenital nonautoimmune hyperthyroidism, and autonomous adenomas. Recent studies have shown that these three syndromes are caused by similar activating mutations of the TSH receptor gene (TSHR), and that the consequences of these mutations on the physiology and gene expression of the thyroid are qualitatively, but not quantitatively, similar. The three syndromes and two suggested unrecognized variants are in fact facets of the same disease, genetic hyperthyroidism due to TSHR mutations, the expression of which depends on the intensity of activation, its timing, and on the number of affected cells.

Abstract. Thirty-four members of a single family were studied and 9 of them were found to be suffering from hyperthyroidism associated wiht diffuse goitre. Exophthalmos was absent and transmission seemed to be independent of HLA type. Four of the 9 were studied prior to treatment but in all cases serum immunoglobulin levels were normal, antithyroglobulin and antimicrosomal antibodies absent, thyroid stimulating antibodies negative and the lymphocyte transformation responses to mitogens not different from those of controls. The results of testing the euthyroid family members were similarly negative, except in the case of a woman with type I diabetes mellitus who showed a low titre of antimicrosomal antibody. Seven of the patients underwent subtotal thyroidectomy. Lymphocytic infiltration of the excised portion was rarely present. Four of the glands were subjected to immunofluorescent and electron microscopy but neither immunosecreting cells nor immune complex deposits were found. These results point to the existence of a non-autoimmune form of goitrous hyperthyroidism, different from Graves' disease.