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| DiseaseID |
HGD66 |
| Genetic
Disorder |
Lynch Syndrome
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| Gene
Name |
mutS homolog 2, colon cancer, nonpolyposis type 1 (E. coli) |
| Description |
Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is characterized by a risk of colorectal cancer and other cancers of the endometrium, ovary, stomach, small intestine, hepatobiliary tract, upper urinary tract, brain, and skin. HNPCC is subdivided into Lynch Syndrome I (familial colon cancer) and Lynch Syndrome II (other cancer of the gastrointestinal system or the reproductive system). The increased risk for these cancers is due to inherited mutations that degrade the self-repair capability of DNA. Lynch syndrome was named in honor of Dr. Henry T. Lynch, professor of medicine at Creighton University Medical Center.
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| Symptoms |
People with Lynch syndrome may experience:
Colon cancer that occurs at a younger age, especially before age 45
A family history of colon cancer that occurs at a young age
A family history of endometrial cancer
A family history of other related cancers, including ovarian cancer, kidney cancer, stomach cancer, small bowel cancer, liver cancer or other cancers
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| Causes |
Lynch syndrome runs in families in an autosomal dominant inheritance pattern. This means that if one parent carries a gene mutation for Lynch syndrome, there's a 50 percent chance that mutation will be passed on to each child.
The defective genes inherited in Lynch syndrome are responsible for correcting mistakes in DNA. DNA is the genetic material that contains instructions for every chemical process in the body. As your cells grow and divide, they make copies of their DNA and it's not uncommon for some minor mistakes to occur. Normal cells have mechanisms to recognize mistakes and repair them. But people who inherit one of the abnormal genes associated with Lynch syndrome lack the ability to repair these minor mistakes. An accumulation of these mistakes leads to increasing genetic damage within cells and eventually can lead to the cells becoming cancerous. |
| Diagnosis |
The Amsterdam clinical criteria identifies candidates for genetic testing, and genetic testing can make a diagnosis of Lynch syndrome. Genetic testing is commercially available through Myriad Genetics, and consists of a blood test.
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| Treatment |
Surgery remains the front-line therapy for HNPCC. There is an ongoing controversy over the benefit of 5-FU based adjuvant therapies for HNPCC-related colorectal tumours, particularly in Stage I and II. |
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