repost: Genomics|Genetic Testing|EGAPP Recommendations|Lynch Syndrome

About Lynch Syndrome Lynch syndrome refers to individuals with hereditary predisposition to colorectal cancer (CRC) and other malignancies as a result of an inherited mutation in a specific type of gene known as a mismatch repair (MMR) gene. Lynch syndrome includes those with an existing cancer as well as those who have not developed cancer. * Also referred to as hereditary nonpolyposis colorectal cancer (HNPCC) * Autosomal dominant inheritance pattern (50% risk to offspring to inherit the gene mutation) * The lifetime risk for CRC in individuals with Lynch syndrome reported in the literature ranges from approximately 20-80%, dependent upon: o Gene involved o Sex of the individual o Population studied * Mean age of onset of CRC is approximately 45 years * Increased risk for other malignancies including: endometrial, ovarian, urinary tract, gastric, small bowel, pancreatic, and sebaceous skin tumors