Presentation and Follow-up of Familial Adenomatous Polyposis: Differences Between APC and MUTYH Mutations

Abstract

BackgroundFamilial adenomatous polyposis is described as one of the common two types of genetic disorders: APC and MUTYH gene associated polyposis syndrome and the clinical differences between the two can sometimes be unclear. Materials and methodsA retrospective analysis and comparison was made of clinical, surgical, and histological criteria, mutation types and the long-term results of patients who underwent genetic analysis which resulted in the diagnosis of familial adenomatous polyposis between 1984 and 2018. ResultsOf the total 71 patients included in the study, 14 were identified with the MUTYH gene, and 57 with the APC mutation. In patients with the APC mutation, 63% had duodenal adenoma, 61% gastric polyp and 54% had desmoid tumor. Of the patients with the MUTYH mutation, 21% had duodenal adenoma and 21% were diagnosed with gastric polyps. In 21% of the patients with APC mutation, the polyp count was <100, and 64% of those with the MUTYH mutation had >100 polyps in the colon No statistical difference was determined between the groups in respect of the proportion of patients with >100 polyps. ConclusionThe pre-operative genetic testing of patients with polyposis coli will be useful in determining the future clinical outcome and helpful in guiding an informed decision as to whether to apply surgical treatment. It is useful to determine the colonic and extra-colonic involvement of genetic mutation diseases in patients with familial adenomatous polyposis.