[Hereditary colorectal cancer].

HNPCC and FAP are inherited diseases with a lifetime risk of colorectal cancer (CRC) of 80-100% in gene carriers. Disease-causing mutations have been identified in the APC gene at FAP and in MMR genes at HNPCC. In FAP-patients, screening has reduced the prevalence of CRC by 55%, and the survival rate has improved considerably. For HNPCC-patients, 77% of CRCs found by screening were Duke' A or B, and survival after CRC has improved significantly since 1990. Continuous central registration in the HNPCC and Polyposis registers is recommended to ensure identification of high-risk families and evaluate the effect of screening.