The purpose of this study is to test the hypothesis that Gitelman syndrome (GS) can be diagnosed using a simple clinical protocol. GS is an inherited kidney disease that usually shows up in patients as low blood potassium levels. Currently, no commercial genetic test for GS exists. Currently, GS is diagnosed based upon clinical findings but this method is not precise and often not reliable. Thus, in order to develop new treatments specific for GS patients, a more exact method of diagnosis would be of benefit.