CYP24A1 and Hypercalcemia: The mutant CYP24A1 enzymes revealed complete or near-complete loss of function, characterized by a weak binding of 1,25-dihydroxyvitamin D3 to 24-hydroxylase, leading, in the end, to hypercalcemia, nephrolithiasis and pseudovitamin D-deficient rickets [159,160].