Idiopathic infantile hypercalcemia in children with chronic kidney disease due to kidney hypodysplasia.

Background: Idiopathic infantile hypercalcemia (IIH) etiologies include pathogenic variants in CYP24A1, leading to increased 1,25(OH) D, hypercalciuria and suppressed parathyroid hormone (PTH), and in SLC34A1 and SLC34A3, leading to the same metabolic profile via increased phosphaturia. IIH has not been previously described in CKD due to kidney hypodysplasia (KHD).

Methods: Retrospective study of children with bilateral KHD and simultaneously tested PTH and 1,25(OH)D, followed in a tertiary care center between 2015 and 2021.