POLD1 and mismatch repair cancer syndrome 1: Within the list of potentially pathogenic variants, we analyzed whether these variants were present in any of the known CRC predisposing genes, i.e, mismatch repair (MMR) genes, APC, POLD1, POLE, SMAD4, BMPR1A, MUTYH, NTHL1. In three individuals, variants in the MMR genes MSH2, MSH6 (three variants) and PMS2 were identified (S4 Table), but based on microsatellite instability or immunohistochemistry analyses none of these variants resulted in MMR deficiency.