In agreement with previous reports [2,3], CRC in our series were diagnosed at younger ages in individuals carrying mutations in highly penetrant MMR genes (mean age: 45.2 and 46.7 years for MLH1 and MSH2 vs. 56.3 and 58.8 years for MSH6 and PMS2, respectively). This evidence concerns the gene MRC1 and colorectal carcinoma.