Cinacalcet treatment experience in hereditary vitamin D resistant rickets.

Background Hereditary vitamin D resistant rickets (HVDRR) is a bone disorder characterized by a phenotype of rickets with onset at early stage of life with elevated alkaline phosphatase, hypocalcemia, hypophosphatemia, hyperparathyroidism and elevated levels of 1,25-dihydroxyvitamin D (calcitriol) as a consequence of the resistance of the vitamin D receptor (VDR). Mutations in the DNA-binding domain of the VDR of the vitamin D receptor have been characterized by a lack of response to traditional treatment with calcium and calcitriol. Secondary hyperparathyroidism and hypophosphatemia are the main factors in its pathogenesis.