CLDN10 is expressed at all tight junction in the ISOM TAL and in a significant percentage of tight junctions in the CTAL [29,30]; here, it is important for normal NaCl reabsorption by these tubular segments, as shown by the phenotype of cKO mice as well as that of patients with HELIX syndrome who exhibit a renal loss of NaCl with secondary hyperaldosteronism [4,5,6,7,8,9,10]. The gene discussed is CLDN10; the disease is helix rolling.