Hypoparathyroidism (HP), a group of heterogeneous disorders characterized by hypocalcemia and hyperphosphatemia due to inadequate PTH secretion or signaling, is a relatively rare endocrine disease, with the exception of postsurgical HP, which is a relatively common condition. The availability of genetic tools and the characterization of specific antibodies against the calcium sensing receptor (CaSR) has helped to classify the different forms of congenital or acquired, non-surgically determined forms of HP, so that few cases can be defined as idiopathic today. Still, precise genetic workup protocols and epidemiological studies on the prevalence and incidence of the various etiologies of HP are needed in order to better classify patients with HP. Bone quality assessment in HP along with a better characterization of the skeletal disturbances, due to the missing action of PTH on bone cells, are advisable. Guidelines on the management of HP are still lacking. HP is the only endocrine condition for which a proper replacement therapy with the missing hormone is not still available. Conventional treatment with calcium and 1a-hydroxylated vitamin D metabolites relieves symptoms of hypocalcemia but it fails in restoring a physiologic calcium and phosphate homeostasis and a normal bone metabolism, since PTH action on kidney and bone is lost. Several trials have tested the effect of teriparatide (PTH1-34) and full length PTH(PTH1-84) on mineral and skeletal homeostasis. PTH replacement therapy, alone or in combination with calcitriol, may restore a more physiological bone metabolism and dynamics, as demonstrated by bone quality studies. Larger and longer randomized intervention trials are needed in order to test PTH toxicity and long-term benefits on bone, kidney, quality of life, and other systems not directly related to mineral homeostasis.
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