Dent's disease--a nephrolithiasis disorder associated with defective receptor-mediated endocytosis

Dent's disease, a renal tubular disorder characterized by low-molecular-weight proteinuria (LMWP), hypercalciuria, and nephrolithiasis, is due to inactivating mutations in the x-linked renal specific chloride channel CLC-5. CLC-5 belongs to the family of voltage-gated chloride channels, which function as homodimeric proteins with each subunit consisting of 18 helices and a chloride selectivity filter, i.e. pore. None of the 15 CLC-5 missense mutations reported in patients with dent's disease involves the chloride selectivity filter, but 12 of these are clustered around the interface of the two subunits, thereby emphasising the important role for the interaction between the two subunits at the interface of the homodimeric CLC-5. In the kidney, CLC-5 forms part of the receptor-mediated endocytic pathway, and defects in this pathway due to a loss of CLC-5 function, may help to account for the LMWP, hyperphosphaturia, hypercalciuria and nephrolithiasis. The molecular studies and the generation of mouse models of the disease have increased our understanding of the renal tubular mechanisms that regulate mineral homeostasis.