CYP24A1 and chronic kidney disease: Although low calcitriol and increased CYP24A1 expression would suggest higher 24,25(OH)2D concentrations, there is a surprising gradual decrease in 24,25(OH)2D concentrations at CKD stages 3 to 5 [109], indicating reduced 25(OH)D catabolism to 24,25(OH)2D at worsened CKD [110].