Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + At a Glance Download Section PDF Listen ++ Genetically transmitted predisposition to develop colorectal cancers. + Synonyms Download Section PDF Listen ++ Cancer Family Syndrome; Familial Cancer Syndrome; Hereditary Nonpolyposis Colorectal Cancer (HNPCC); Hereditary Nonpolyposis Colorectal Carcinoma. + History Download Section PDF Listen ++ First described by Alder Scott Warthin, an American pathologist, in 1913. + Incidence Download Section PDF Listen ++ Five percent of the colorectal cancer population. + Genetic Inheritance Download Section PDF Listen ++ Both clinical forms of HNPCC are autosomal dominant with a penetrance of 85 to 90%. Two DNA mismatch repair genes are closely linked to the disease: hMSH2 gene in chromosome 2p and hMLS1 gene in chromosome 3p. Mutations in these genes account for 90% of all known HNPCC families. + Pathophysiology Download Section PDF Listen ++ Defective DNA mismatch repair leads to accumulation of mutations. The mutation load can be identified as errors in long tandem repeat sequences, which produce microsatellite instability. + Diagnosis Download Section PDF Listen ++ Familial history, colonic screening examinations, DNA genetic testing. + Clinical Aspects Download Section PDF Listen ++ Two clinical forms described: ++ Lynch Syndrome I: Familial predisposition to early-onset colorectal cancer (mainly right colon). Lynch Syndrome II: Same features and familial predisposition with an associated predisposition for other primary cancers (often female reproductive organs, particularly endometrial carcinoma). This variant is not easily recognized because of the lack of phenotypical expression as familiar adenomatous polyposis. + Precautions before Anesthesia Download Section PDF Listen ++ All precautions before anesthesia will be dictated by those associated with the patient's underlying medical condition. + Anesthetic Considerations Download Section PDF Listen ++ Anesthetic considerations are those associated with the surgical procedure only or any associated medical conditions. + Pharmacological Implications Download Section PDF Listen ++ No specific pharmacological implications except for patients receiving chemotherapy. + References Download Section PDF Listen ++de Vos tot Nederveen Cappel WH, Nagengast FM, Griffioen G, et al: Surveillance for hereditary nonpolyposis colorectal cancer: A long-term study on 114 families. Dis Colon Rectum 45:1588, 2002. ++Mitchell RJ, Farrington SM, Dunlop MG, et al: Mismatch repair genes hMLH1 and hMSH2 and colorectal cancer: A HuGE review. Am J Epidemiol 156:885, 2002. [PubMed: 12419761] ++Wagner A, Tops C, Wijnen JT, et al: Genetic testing in hereditary non-polyposis colorectal cancer families with a MSH2, MLH1, or MSH6 mutation. J Med Genet 39:833, 2002. [PubMed: 12414824]