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    Hypercalcemia, Hypercalciuria and Elevated Calcitriol Concentrations with Autosomal Dominant Transmission Due to CYP24A1 Mutations: Effects of Ketoconazole Therapy

    The CYP24A1 gene encodes the enzyme 1,25-dihydroxyvitamin D-24-hydroxylase, which inactivates, 1,25 dihydroxyvitamin D.  The authors describe a patient with intermittent hypercalcemia, hypercalciuria, elevated serum 1,25-dihydroxyvitamin D, undetectable serum 24,25-dihydroxyvitamin D, nephrolithiasis, and reduced bone mineral density, who had a mutation of CYP24A1.  When the patient was treated with the cytochrome 3A inhibitor, ketoconazole for 2 months, he demonstrated statistically significant reductions in urinary calcium, 1,25-dihydroxyvitamin D and serum calcium concentrations.


    Tebben PJ, Milliner DS, Horst RL, Harris PC, Singh RJ, Wu Y, et al