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Hereditary nonpolyposis colon cancer

Orpha number ORPHA144
Synonym(s) Familial nonpolyposis colon cancer
Familial nonpolyposis colorectal cancer
Hereditary nonpolyposis colorectal cancer
Lynch syndrome
Prevalence Unknown
Inheritance Autosomal dominant
Age of onset Adult
  • C18
  • C1333990
  • D003123
  • 10051981
  • 315058005


Hereditary nonpolyposis colorectal cancer (HNPCC) is the most frequent form of hereditary colorectal cancer.

In the families identified based on these criteria, the affected subjects primarily develop colorectal, with or without endometrial cancers, with a cumulative risk of 70-80% at 70 years.

The gene(s) associated with the HNPCC syndrome belong to the family of DNA mismatch repair (MMR) genes involved in the control of replication. Mutations in the MSH2 (MutS homolog 2, 16 exons), MLH1 (MutL homolog 1, 19 exons) and MSH6 (2p16, 10 exons) genes have been detected in respectively, 35, 25 and 2% of the cases. No genetic mutation has been found in about a third of the patients.

Its diagnosis is based on the presence of three criteria, defined in 1991 in Amsterdam, and revised in 1999: i) at least three subjects with histologically proven cancers belonging to the narrow spectrum of the HNPCC syndrome (hereditary predisposition to colorectal and endometrial adenocarcinomas), ii) paired with a first-degree family relationship over at least two generations and iii) at least one of the cancers diagnosed before the age of 50 years.

The disease is transmitted as an autosomal dominant trait.

Monitoring by colonoscopy is recommended every 2 years, as of 20 years of age, for individuals carrying a constitutional mutation in the MSH2, MLH1 or MSH6 gene. Gynecological monitoring of women over 30 years old is also recommended. The treatment of these cancers is the same as that given in the absence of any predisposition. No preventive treatment exists.

Expert reviewer(s)

  • Dr Sylviane OLSCHWANG

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Detailed information

Review article
  • IT (2010)
  • EN (2010)
Clinical practice guidelines
  • DE (2013)
  • EN (2013)
  • FR (2012)
Diagnostic criteria
  • EN (1999,pdf)
Guidance for genetic testing
  • EN (2012,pdf)
Article for general public
  • IT (2006)
Clinical genetics review
  • EN (2014)
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The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment.