[Familial hypercalcemia and hypophosphatemia: importance in differential diagnosis of disorders in calcium-phosphate metabolism].

[familial hypocalciuric hypercalcemia]

Hypercalcemia and hypophosphatemia are symptoms of two relatively rare hereditary diseases and are extraordinarily important from the standpoint of the differential diagnosis . Mutation in calcium sensing receptor gene (CaSR ) clinically manifests as familial hypocalciuric hypercalcemia (FHH ) or as the much more serious neonatal hyperparathyreosis . Hypercalciuric hypocalcemia is extremely rare . Prognosis for the most frequent mutations in the CaSR gene FHH is considered benign ; nevertheless , if overlooked it can lead to an incorrect diagnosis of primary hyperparathyreosis , which has a fundamentally different prognosis and treatment . Familial hypophosphatemia sometimes occurs as hereditary rickets , which is a consequence of insufficient production of vitamin D-hormone or abnormal function of vitamin D receptors (VDR ). The disease manifests as X-linked dominant hypophosphatemic rickets or autosomal dominant hypophosphatemic rickets . Autosomal recessive form is very rare . Oncogenic hypophosphatemia should be excluded in differential diagnosis . In this review the issues of pathogenesis , differential diagnosis and treatment of FHH and hypophosphatemic rickets are discussed .