[Updates on rickets and osteomalacia: vitamin D dependency]

Vitamin D dependency was first termed for patients resembling vitamin D-deficiency but require high doses of vitamin D administration. Now this disease is known to be caused by defective conversion of 25OHD to 1,25 (OH) 2D, which is termed vitamin D-dependent rickets type 1 or 1α-hydroxylase deficiency, or by end-organ unresponsiveness to 1,25 (OH) 2D, which is called vitamin D-dependent rickets type 2 or hereditary vitamin D-resistant rickets. Recent advance in the molecular analysis of these diseases revealed variety in the presentation and in the inheritance patterns. Molecular diagnosis would be preferable for some atypical cases for adequate therapy.