CYP2C19 and gastroesophageal reflux disease: All three groups exhibited comparable DeMeester scores when PPIs were discontinued 72 hours before the ambulatory pH study.<h4>Conclusion</h4>CYP2C19 RMs and UMs on chronic PPI with refractory GERD symptoms exhibited greater esophageal mucosal inflammation, as observed both endoscopically and histologically, and more were found to have hypotensive LES resting pressures and more were offered esophageal dilatation.