Lynch syndrome is the most common syndrome of hereditary colorectal cancer

Lynch syndrome is the most common syndrome of hereditary colorectal cancer, accounting for 2%-3% of all colorectal cancers.

Lynch syndrome, also known as Lynch syndrome, is an autosomal dominant genetic disease, in which patients are born with mismatch repair gene mutations, the essence of which lies in the genetic defects of MLH1, MSH2, MSH6, PMS2 and EPCAN genes.

The risk of colorectal cancer in patients with Lynch syndrome is 8.7% to 61%, and the risk of cancer in MLH1 and MSH2 mutation carriers is 33% to 61%. Carriers of MSH6 and PMS2 mutations have an 8.7%-44% risk of developing colorectal cancer.

It is therefore recommended that carriers of MLH1 and MSH2 mutations undergo colonoscopy starting at the age of 20 to 25 years, or two to five years before the age of onset of the youngest patient in the family. Carriers of MSH6 and PMS2 mutations are recommended to undergo colonoscopy starting between 25 and 30 years of age, or two to five years earlier than the age of onset for the youngest patient in the family.