MUTYH-associated polyposis: Review and update of the French recommendations established in 2012 under the auspices of the National Cancer Institute (INCa)

MUTYH-associated polyposis (MUTYH-associated polyposis, MAP) is an autosomal recessive inheritance disorder related to bi-allelic constitutional pathogenic variants of the MUTYH gene which was first described in 2002. In 2011, a group of French experts composed of clinicians and biologists, performed a summary of the available data on this condition and drew up recommendations concerning the indications and the modalities of molecular analysis of the MUTYH gene in index cases and their relatives, as well as the management of affected individuals. In view of recent developments, some recommendations have become obsolete, in particular with regard to the molecular analysis strategy since MUTYH gene has been recently included in a consensus panel of 14 genes predisposing to colorectal cancer. This led us to revise all the points of the previous expertise. We report here the revised version of this work which successively considers the phenotype and the tumor risks associated with this genotype, the differential diagnoses, the indication criteria and the strategy of the molecular analysis and the recommendations for the management of affected individuals. We also discuss the phenotype and the tumor risks associated with mono-allelic pathogenic variants of MUTYH gene.