An international collaborative group met in Amsterdam in 1991 to establish guidelines for identifying Lynch Syndrome families.
- Three affected relatives with colorectal cancer, one of them a first-degree relative of the other two.
- AND colorectal cancer in at least 2 generations.
- One family member diagnosed with colorectal cancer before age 50 years.
- AND Familial Adenomatous Polyposis (FAP) should be excluded.
Amsterdam Criteria II
Because genetically abnormal families were identified that did not meet the above guidelines, a revised criteria were published in 1999.
- There should be at least three relatives with a Lynch Syndrome –associated cancer (colorectal, endometrial, small bowel, ureter or renal pelvis).
- One should be a first-degree relative of the other two.
- At least two successive generations should be affected.
- At least one should be diagnosed before age 50 years.
- Familial adenomatous polyposis should be excluded in the colorectal cancer cases.
Revised Bethesda Guidelines
A third set of criteria can also be used to identify Lynch Syndrome families.
- Colorectal cancer diagnosed in an individual younger then 50 years.
- Presence of synchronous metachronous colorectal, or other Lynch Syndrome–associated tumors in an individual regardless of age.
- Colorectal cancer with MSI-high pathologic associated features diagnosed in an individual younger than 60 years.
- Colorectal cancer or Lynch Syndrome-associated tumor diagnosed in at least one first –degree relative younger than 50 years.
- Colorectal cancer or Lynch Syndrome-associated tumor diagnosed at any age in two first-degree or second-degree relatives.