A novel CYP24A1 genotype associated to a clinical picture of hypercalcemia, nephrolithiasis and low bone mass

Mutations of the CYP24A1 gene, encoding for the enzyme 25(OH)D-24-hydroxylase, can cause hypercalcemia, hypercalciuria, nephrolithiasis and nephrocalcinosis. We report the case of a 22-year-old male patient with recurrent nephrolithiasis, nephrocalcinosis, hypercalcemia with low parathyroid hormone levels, hypercalciuria and low bone mass. Gene sequencing showed that the patient had compound heterozygous mutations including a novel genotype of the CYP24A1 gene. Genetic CYP24A1 testing and biochemical analyses were offered to other family members; the father was heterozygous for the same novel genotype and was also affected with recurrent nephrolithiasis.