However, high-penetrance mutations in known CRC predisposing genes, such as the mismatch repair (MMR) genes, APC, MUTYH (MYH), SMAD4, BMPR1A, STK11/LKB1, PTEN, AXIN2, POLE, and POLD1 explain only around 5% of these cases [4]–[6]. The gene discussed is APC; the disease is colorectal carcinoma.