[Rickets/osteomalacia due to tubular dysfunction]

Proximal tubular cells play important roles in the homeostasis of Ca, P and acid-base balance. Tubular dysfunction could cause impairment of bone mineralization. In this review, the mechanisms underlying development of rickets/osteomalacia associated with tubular disorders in conjunction with its molecular mechanisms are described. Among the tubular functions, reabsorption of phosphate via Na-Pi cotransporter, endocytotic reabsorption of VitD-DBP complex mediated by megalin and cubilin, and acid-base regulation are most important for bone mineralization. As clinical manifestations, Fanconi syndrome is most common. Rickets in Dent disease is also described.