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The diagnostic algorithm of thyroid diseases, the most frequent dysendocrine condition, can be today integrated by the newly developed molecular methodologies. From the early diagnostic approaches, centered on the assessment of thyroid function, either by in vivo radioisotopic techniques, or by in vitro radioimmunological measurement of hormone plasma concentrations, it is nowadays possible to precisely define the molecular events triggered by the iodothyronine signal at the level of target tissues. In this brief review will be discussed the recent progresses on cloning and characterization of several genes involved in the regulation of thyroid differentiation, ability to trap iodine, synthesis and secretion of iodothyronines, regulation of thyroid function by TSH, transduction of the hormonal signal to subcellular structures involved in the translation of the hormone message in specific biological, effects such as those on metabolic homeostasis, cell proliferation and differentiation. It will be also discussed the most recent advancements on the genetics of thyroid diseases which have allowed to characterize the molecular basis of several thyropathies such as congenital hypothyroidism, thyroid hormone resistance syndrome, hyperthyroidism or hypothyroidism caused by TSH-receptor alterations, molecular abnormalities of oncogenes or tumor suppressor genes which are associated with benign or malignant thyroid cell transformation. The most recent developments of the diagnostic procedures of thyroid diseases, also in their pre-clinical stage, will be also reviewed together with a brief highlight on the most recent treatment options, centered on prophylactic therapeutic intervention or on the development of gene therapy strategies which will be possibly applied in a near future.

Thyroid diseases include forms amenable to alterations in genes involved in functional regulatory processes, morphofunctional development, hormogenesis and hormone functional expression. A number of genetic diseases are consequent of a point mutation, the cause of the replacement of a single nucleotide which may alter the chromosome number structure and morphology. Among structural anomalies there is deletion, duplication, inversion, translocation and isochromosome formation. Among thyroid diseases, the underlying cause of some of them is represented by alterations in genes regulating the thyroid function, alterations in genes of thyroid differentiation. Less common are the alterations in genes connected with the synthesis of proteins involved in hormone transport while alteration in genes encoding thyroid hormone receptors and in genes involved in thyroid neoplastic transformation are extensively described in literature. The studies of molecular biology will allow in-dept knowledge of the pathogenesis of thyroid disease associated to genetic alterations.