GI: gastrointestinal, GERD: gastroesophageal reflux disease, IBD: inflammatory bowel disease, PUD: peptic ulcer disease, PPI: proton pump inhibitor, UGIB: upper gastrointestinal bleeding, NAFLD: non-alcoholic fatty liver disease, BMI: body mass index, ALT: alanine transaminase, AST: aspartate transaminase, GGT: gamma-glutamyl transpeptidase, ALP: alkaline phosphatase, LDL-C: low-density lipoprotein cholesterol. This evidence concerns the gene GGTLC1 and gastroesophageal reflux disease.