CYP24A1 and vitamin D deficiency: Importantly, the simultaneous measurement of 25(OH)D and 24,25(OH)2D3 as it was done in our study allows to improve the identification of individuals with vitamin D deficiency, CYP24A1 lack of function mutations, vitamin D intoxication or uncontrolled 1,25(OH)2D production in granulomatous diseases [22, 55].