A third study [25] including criteria for diagnosis of ZES in 63 MEN1 patients (ZES/MEN1) used the following criteria for diagnosis of ZES: pathology only (11%), biochemical and pathology together (24%), biochemical only (64%), and increased FSG with imaging (2%), and the basis of the biochemical diagnosis was >10× ULN for FSG (71%) when the PPI was not stopped, >2× increase FSG without PPI, or >5× ULN with PPI, and in 16% FSG the above criteria was not fulfilled. The gene discussed is MEN1; the disease is Zollinger-Ellison syndrome.