The only study of considerably similar design by Kugai et al. reported low-normal 24,25(OH)2D3 in patients with Cushing’s syndrome [10], which is consistent with our result, as well as some experimental works indicative of suppression on CYP24A1 expression by glucocorticoids in human osteoblasts [23], liver and intestine [21] and in rat brain and myocardium [22]. This evidence concerns the gene CYP24A1 and Cushing syndrome.