Therapy-Resistant Hypercalcemia in a Patient with Inactivating CYP24A1 Mutation and Recurrent Nephrolithiasis: Beware of Concomitant Hyperparathyroidism.

K David, R Khalil, H Hannon, P Evenepoel, B Decallonne

Journal: Calcified tissue international 2021;107(5):524-528

PMID: 32743688

Abstract

We describe a case harboring a homozygous CYP24A1 mutation with mild loss of function, first presenting with recurrent nephrolithiasis from the age of 22 onward, initially associated with hypercalcemia and low PTH concentrations. Over the years, hyperparathyroidism developed, resulting in more severe hypercalcemia. Also, kidney function deteriorated, most probably as a consequence of biopsy-proven nephrocalcinosis. Conventional treatment options for CYP24A1 mutation were not effective and/or tolerated (avoidance of sun exposure, diet, pamidronate, itraconazole). A total parathyroidectomy was performed resulting in a normocalcemic hypoparathyroidism without need for treatment with vitamin D analogs, a positive bone mineral balance and an improved kidney function.

Address: Department of Chronic Diseases and Metabolism, Laboratory of Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49, ON1 box 902, 3000, Leuven, Belgium. [email protected].; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium. [email protected].; Department of Chronic Diseases and Metabolism, Laboratory of Clinical and Experimental Endocrinology, KU Leuven, Herestraat 49, ON1 box 902, 3000, Leuven, Belgium.; Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium.; Department of Nephrology, Maria Middelares Hospital Ghent, Ghent, Belgium.; Department of Immunology and Microbiology, Laboratory of Nephrology, KU Leuven, Leuven, Belgium.; Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium.

DOI: 10.1007/s00223-020-00738-8

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https://dx.doi.org/10.1007/s00223-020-00738-8

MeSH Terms: Calcium, Drug Resistance, Humans, Hypercalcemia, Hyperparathyroidism, Mutation, Nephrolithiasis, Recurrence, Vitamin D3 24-Hydroxylase