In the lithogenic state, the evolutionary sequences of gallstone formation are characterized by the initial accumulation of mucin gel, followed by the appearances of liquid crystals and/or anhydrous cholesterol crystals and classical plate-like cholesterol monohydrate crystals, and then agglomerated cholesterol crystals, sandy stones, and gallstones in CCK knockout mice fed the lithogenic diet for 8 weeks [133,134]. The gene discussed is CCK; the disease is gallstones.