Of note, the POLD1 carrier had hyper-mutated colon adenocarcinoma, the BMPR1A carrier had a hamartomatous polyp, and the SMAD4 carrier had a history of a juvenile polyp, consistent with the identified genes, although the patients with BMPR1A and SMAD4 variants do not meet the current GT criteria for the respective genes [30]. Here, SMAD4 is linked to juvenile polyp.