We did not detect an increased risk of LBC for PALB2, CDH1 or CHEK2. Conclusion: The overall PGV detection rate was 11.59%, with similar rates of BRCA1/2 (7.28%) PGVs as for other actionable PGVs (7.46%), indicating a benefit for extended panel genetic testing in LBC. The gene discussed is CHEK2; the disease is CDH1-related diffuse gastric and lobular breast cancer syndrome.