Subjecting over 100 KS-WNK1–KO mice and littermate controls to various potassium maneuvers designed to manipulate NCC phosphorylation across a wide physiologic range, we found that KS-WNK1–KO mice exhibited reduced pNCC during hypokalemia and increased pNCC relative to WT mice during hyperkalemia. The gene discussed is SLC12A3; the disease is Hypokalemia.