Hereditary syndrome	Gene	Genetic pattern	Risk management suggestions
Hereditary diffuse gastric cancer	CDH1	Autosomal dominance	Prophylactic gastrectomy is recommended for CDH1 mutation carriers age 8‐40‐years old; For CHD1 carriers who do not undergo gastrectomy, endoscopy is recommended every 6‐12 months with random multi‐point biopsy; The risk of breast cancer in female CDH1 mutation carrier is high and regular breast imaging examination is advised
Lynch syndrome	EPCAM, MLH1, MSH2, MSH6, PMS2	Autosomal dominance	Upper gastrointestinal endoscopy with careful assessment of the duodenum can be considered for some patients or offspring of Asian family origin
Juvenile polyposis syndrome	SMAD4, BMPR1A	Autosomal dominance	Upper gastrointestinal endoscopy screening is advised after the age of 15. If polyps are found, they should be reexamined every year; If no polyps are found, reexamination every 2‐3 years is advised
Boytz Jegher syndrome	STK11	Autosomal dominance	Upper gastrointestinal endoscopy screening is advised from late adolescence and reexamination every 2‐3 years
FAP/AFAP	APC	Autosomal dominance	Currently, not enough evidence to suggest screening for gastric cancer in FAP/AFAP persons. FAP is more prone to duodenal cancer and while screening for it, the stomach can also be examined. Currently, upper gastrointestinal endoscopy is suggested for those aged ≥25‐30 years old, and the frequency of reexamination should be determined based on characteristics of duodenal polyps

Abbreviations: FAP, familial adenomatous dysplasia; AFAP, attenuated FAP; EPCAM, Epithelial Cell Adhesion Molecule; H1, MutL Homolog 1; PMS2, Postmeiotic Segregation Increased Homolog 2; SMAD4, SMAD family member 4; BMPR1A, Bone Morphogenetic Protein Receptor Type 1A; STK11, Serine/Threonine Kinase 11; APC, Adenomatous Polyposis Coli.

CDH1 germline gene mutation detection is recommended for families meeting the clinical diagnostic criteria of hereditary diffuse gastric cancer (recommended grade: III; Evidence 2B)