文摘
MUTYH polyposis (MAP) is responsible for approximately 10 and 30?% of classical and attenuated forms of adenomatous colorectal polyposes, respectively. The underlying molecular mechanism is a biallelic germline mutation of the MUTYH gene responsible for the failure of the base excision repair (BER) DNA repair system with subsequent accumulation of somatic transversion mutations. The cumulative risk of colorectal cancer is very high in the absence of adequate care. Lifelong close colonoscopic surveillance with polypectomies is recommended. Surgery (total rather than partial colectomy) is required when polyp burden exceeds the number that could be safely managed by endoscopy and/or in case of colorectal cancer. Upper gastrointestinal endoscopy is also recommended to detect and to treat duodenal lesions. An increased risk of colorectal cancer is reported in relatives of MAP patients carrying a monoallelic MUTYH mutation. According to the opinion of the majority of experts, these individuals are therefore candidates for colonoscopic surveillance as recommended for first-degree relatives of a patient with sporadic colorectal cancer.