POLD1 and polyposis: These genes have been studied by a Spanish group in 529 kindred (441 with familial nonpolyposis CRC and 88 with polyposis) using massively parallel sequencing identifying 7 genetic variants (the POLE p.L424V mutation was associated with polyposis, CRC and oligodendroglioma) and 6 POLD1 variants with strong evidence for pathogenicity were identified in nonpolyposis CRC families [43].