Zollinger–Ellison syndrome (ZES), first described in 1955 [1], is characterized by gastric acid hypersecretion due to ectopic secretion of gastrin by a neuroendocrine tumor (NET) (gastrinoma) resulting in severe peptic ulcer disease (PUD)/gastroesophageal reflux disease (GERD), which is often refractory to standard PUD treatments [2,3,4,5,6,7,8,9,10,11]. This evidence concerns the gene GAST and gastroesophageal reflux disease.