In a prospective study of 261 ZES patients from the NIH [126], 42% of patients with sporadic ZES and 52% of MEN1/ZES patients had esophageal symptoms (primarily heartburn) at initial presentation [126], which compares to 29–61% in other series [116,126,147,233,234,235,236], demonstrating that chronic GERD symptoms are not infrequent in these patients. Here, MEN1 is linked to Zollinger-Ellison syndrome.