title: Idiopathic Infantile Hypercalcemia, Presenting in Adulthood--No Longer Idiopathic Nor Infantile: Two Case Reports and Review.
abstract: We present two unrelated cases of young adults with hypercalcemia, hypercalciuria, and nephrocalcinosis. Both had suppressed intact parathyroid hormone levels and high 1,25 vitamin D levels after only brief, low-dose, over-the-counter vitamin supplementation. Neither had evidence of a granulomatous disorder. Their presentation mimicked that of 1,25 hydroxy vitamin D intoxication. In both patients, the diagnosis of idiopathic infantile hypercalcemia was confirmed with immeasurably low 24,25 vitamin D levels. Both were found to have a loss-of-function mutation in the CYP24A1 gene, which encodes the vitamin D-metabolizing enzyme 25-hydroxyvitamin D 24-hydroxylase.
authors.forename: Kory A
authors.initials: KA
authors.lastname: Tray
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Laut
authors.forename: Arya
authors.initials: A
authors.lastname: Saidi
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000175:diagnosis* / Q000235:genetics*; D053565:Hypercalciuria / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D009154:Mutation; D009397:Nephrocalcinosis / Q000175:diagnosis* / Q000235:genetics*; D065668:Vitamin D3 24-Hydroxylase / Q000235:genetics*
chemical_list: C585549:CYP24A1 protein, human; D065668:Vitamin D3 24-Hydroxylase