The Italian Register of primary hypoparathyroidism

Introduction

Calcium is an important bioinorganic ion performing a variety of intra- and extra-cellular functions and playing an important role in maintaining normal physiologic processes. It is also an im­portant component or co-factor required for the proper function­ing of coagulation factors and adhesion molecules. Homeostasis of calcium and phosphorus is maintained by a combined activity of the calciotropic hormones: parathyroid hormone (PTH), Vitamin D [25 OH₂D₃ and 1-25 (OH)₂D₃], and calcitonin (CT). PTH, the product of the parathyroid glands, regulates serum calcium concentrations and bone metabolism. In turn serum calcium concentrations regulate PTH secretion by means of a calcium-sensing receptor (CaSR) on the surface of parathyroid cells. buy cheap viagra on rx-approved

The term of primary hypoparathyroidism refers to a group of in­herited disorders in which the relative or absolute deficiency of PTH leads to hypocalcemia and hyperphosphatemia (Table I). These disorders may be caused by developmental defects in the parathyroid glands, by autoimmune endocrinopathies, by defects in PTH synthesis, by impaired regulation of PTH secre­tion, and by defective PTH action. The latter forms termed pseudo-hypoparathyroidism are unique in that PTH secretion is increased rather than deficient.

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