We suggest that the upregulation of TRPV5/6 and of ROMK1 and Maxi-K may contribute to hypocalciuria and hypokalemia in Ncc Ser707X knockin mice and human GS, respectively.
This study revealed the following characteristics of these disorders: 1) subjects with CLCNKB mutations showed one or more biochemical features of Gitelman syndrome (including hypomagnesemia, hypocalciuria, and fractional chloride excretion insensitivity to thiazide administration); and 2) subjects with KCNJ1 mutations appeared to show normal fractional chloride excretion sensitivity to furosemide and thiazide administration.
However, the relationship between the alterations in the NO signalling system observed in this study and the mutations in either Na+-K+-2Cl cotransporter or in a K+ channel ROMK or in Cl- channel ClCNKB in Bartter's syndrome and in Na+-Cl- cotranstransporter in Gitelman's syndrome, recently reported as their primary defects remains to be defined.