Excluding c.1137G>A and c.833-476_1138-463del alterations,20 the remaining identified CDH1 variants in this study were not previously reported in patients with LBC, to our knowledge.21 The identified P/LP CDH1 variants were associated with a positive family history for BC in 5 cases (83.3%; 4 early-onset LBC at age <45 years at diagnosis, 1 also with bilateral LBC manifestation), and 1 (16.7%) case was a sporadic juvenile early-onset LBC (eFigure 2 in Supplement 1). Here, CDH1 is linked to breast cancer.