Calcium and Phosphate Homeostasis is of major importance to a large number of hysiological processes thereby affecting several organ systems typically bone, muscles, kidney, brain with consequences on quality of life and risk of chronic disability.
These diseases often manifest with unspecific symptoms (like seizure, failure to thrive) leading to a severe delay in diagnosis. For several of theses diseases, treatment options are available (or under development) if patients are diagnosed. However, it is only recently that long-term consequences and burden of the diseases have been characterized.
Establishing databases on these rare conditions is crucial. For calcium (Ca) and phosphate (Pi), 3 subthematic groups are identified based on the pathophysiology of the diseases, the multidicplinary care involved and long-term consequences as well as the different research approaches. The PTH dependent diseases covers complicated cases of hyperparathyroid hypercalcemia which cannot be treated by simple parathyroidectomy and genetic syndromes predisposing to hyperparathyroidism. Hypocalcemia covers hypoparathyroidism, autosomal dominant hypocalcemia as well as vitamin D dependent richets (VDDR). Disorders of phosphate imbalance share abnormal bone and teeth structure, as well as a dysregulation of the FGF23 endocrine system.