We have recently shown that mice lacking the ubiquitous Na +-K+-2Cl– cotransporter-1 (Nkcc1, Slc12a2), specifically in insulin-secreting β-cells, develop overweight, nonalcoholic steatohepatitis, and a metabolic syndrome-like phenotype associated with reduced β-cell mass, mild secretory dysfunction, and reduced calorie consumption per unit of BW (41). The gene discussed is INS; the disease is metabolic syndrome.