In order to provide further insight into the relationship between APC exon 12 or exon 13 splicing mutations leading to an in-frame protein, the clinical phenotype, and the potential underlying molecular mechanisms in FAP disease, we retrieved clinical and molecular data of FAP patients bearing truncating mutations that lead to partial or total removal of ARM2 and/or ARM3 and disrupt all downstream APC protein domains [50,53,71,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105] (Table S4). This evidence concerns the gene APC and Familial adenomatous polyposis.