Hypocitraturia Contributing to Nephrolithiasis in a Patient with CYP24A1 Gene Mutation

ABSTRACT Objective There have been several case reports of hypercalcemia due to mutation in CYP24A1, which encodes an enzyme that controls the catabolism of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D to inactive forms. These patients develop nephrolithiasis, nephrocalcinosis, and eventually renal insufficiency. We describe a patient with hypercalcemia and nephrolithiasis due to CYP24A1 mutation with other co-existing factors for renal stone formation. Methods A literature search was conducted using the PubMed and Google Scholar databases for CYP24A1 mutation and hypercalcemia. Publications were selected based the quality of the data and clinical relevance. Results CYP24A1 mutation may lead to hypercalcemia, hypercalciuria, and renal stone formation; however, other risk factors for renal stone formation such as urinary citrate, sodium, oxalate, and uric acid levels need to be evaluated. Conclusions This case highlights the need to evaluate for other renal stone risk factors in patients with CYP24A1 mutation.