CYP24A1 and hypercalcemia, infantile: Hypervitaminosis D in patients with granulomatous diseases, lymphomas, or vitamin D 24-hydroxylase (CYP24A1) loss-of-function mutations (also known as idiopathic infantile hypercalcemia (IIH)5) leads to hypercalciuria, nephrocalcinosis, and renal dysfunctions5–8.