Dental agenesis as a novel phenotypical feature associated with hereditary diffuse gastric cancer in China

Background Hereditary diffuse gastric cancer (HDGC) is an autosomal dominant gastric cancer associated with germline CDH1 mutations. Carriers of CDH1 mutations have a higher risk of developing gastric cancer at a younger age, highlighting the need for a phenotypic feature for early diagnosis and management. Methods We analysed 121 patients with gastric cancer who underwent genetic testing at the National Cancer Center in China. CDH1 mutation status was assessed using next-generation sequencing. Fisher’s exact test and Mann-Whitney U test were performed to compare clinicopathological features between CDH1 -mutated and non-mutated patient groups. Results Among 121 index cases, three CDH1 germline mutation carriers (2.5%) were identified. Mutation carriers were diagnosed at a significantly younger age compared with non-carriers ( p <0.05). Notably, two patients in our cohort exhibited congenital tooth agenesis, a phenotypical feature rarely reported in patients with HDGC and previously undocumented in East Asian cohorts. Conclusion Congenital tooth agenesis represents a phenotypic manifestation associated with CDH1 germline mutations. Awareness of such features could enhance recognition of high-risk individuals and support genetic counselling and surveillance strategies. Further studies are needed to confirm these associations.