Indeed, two groups have reported that WNK4 regulates the paracellular Cl− permeability in MDCK II cells [25,26], and the latest study documented by Chen et al. showed that mice with knockin Cl−-insensitive mutant WNK4 displayed hypertension, hyperkalemia, hyperactive NCC, and the authors concluded that WNK4 is a physiological intracellular Cl− sensor [24]. This evidence concerns the gene WNK4 and Hyperkalemia.