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HNPCC

by Donna Myers
for About.com

Updated: September 4, 2006

About.com Health's Disease and Condition content is reviewed by the Medical Review Board

Definition:

Hereditary nonpolyposis colon cancer (HNPCC) is caused by a mutation in any of five genes. HNPCC is an inherited condition, so if you have it, you were born with it. Approximately 2-5% of colon cancer is caused by HNPCC.

What are the effects of HNPCC?

Most people have about a 6% chance of developing colon cancer at some point in their lives, usually after age 60. People with HNPCC have about an 80% risk of developing colon cancer, usually by age 44. Women with HNPCC also have about a 50% chance of developing uterine cancer.

It's important to note that HNPCC isn't a form of colon cancer. HNPCC is simply a genetic mutation that increases a person's chances of developing colon cancer, like the BRCA mutations and breast cancer.

What do you do about HNPCC?

A typical screening recommendation for people at average risk for colon cancer is to get their first colonoscopy at age 50 and if all is well, have a follow-up colonoscopy in ten years. Since they're in a high-risk category, people with HNPCC are encouraged to have their first colonoscopy at age 20, with follow-up colonoscopies every year or two.

Sources:
  1. Detailed Guide: Colon and Rectum Cancer: Can Colorectal Polyps and Cancer Be Found Early? American Cancer Society. 7 Mar. 2006 [http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_Can_colon_and_rectum_cancer_be_found_early.asp?sitearea=].
  2. Hereditary Non-polyposis Colorectal Cancer. Cleveland Clinic. 29 Oct. 2003. 1 Sep. 2006 [http://www.clevelandclinic.org/registries/inherited/hnpcc.htm].
  3. Komaromy, M. What is HNPCC? Genetic Health. 11 Aug. 2000. 1 Sep. 2006 [http://www.genetichealth.com/CRC_HNPCC_A_Hereditary_Syndrome.shtml].
Also Known As: hereditary nonpolyposis colon cancer, hereditary nonpolyposis colorectal cancer, lynch syndrome

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