The lower levels of the 25(OH)D3 can be explained by the loss of 25(OH)D3 bound to the vitamin D-binding protein in patients with nephrotic proteinuria, impaired ultraviolet B-dependent cutaneous synthesis of cholecalciferol and reduced hepatic 25(OH)D3 production due to uremia, dietary restrictions and less solar exposure in patients with CKD [24]. The gene discussed is GC; the disease is chronic kidney disease.