Endocrine Abstracts

The bioactive form of Vitamin D [1,25(OH)2D3] plays a major role in calcium homeostasis. Moreover, it has potent anti-inflammatory and anti-proliferative properties, and thus is a potential pharmacological agent to treat various refractory diseases. Nevertheless, the doses required to elicit such effects induce hypercalcemia. The activity of 1,25(OH)2D3 is mediated by the vitamin D receptor (VDR), a member of nuclear receptor superfamily. A number of patients with rickets carr...

Idiopathic Infantile Hypercalcemia (IIH) is a rare inborn form of severe vitamin D hypersensitivity, with an estimated incidence of 1:33.000 live birth and a high degree of misdiagnosis. Since the identification of CYP24A1 loss-of-function variants inducing IIH in 2011, over 41 pathogenic variants have been described, and represent the major genetic drivers of IIH1. CYP24A1 encodes the main catalytic hydroxylase of the bioactive form of vitamin D (1,25D3). Upon bind...