Hereditary nonpolyposis colon cancer

the urinary tract cancers are transitional carcinoma of the ureter and renal pelvis; the small bowel cancer is most common in the duodenum and jejunum; and the most common type of brain tumor is glioblastoma.

The diagnosis of HNPCC may be made on the basis of the Amsterdam clinical criteria (listed above) or on the basis of molecular genetic testing for mutations in a mismatch repair gene (MLH1, MSH2, MSH6 or PMS2). Mutations in MLH1 and MSH2 account for 90% of HNPCC. Mutations in MSH6 and PMS2 account for the rest.

HNPCC is inherited in an autosomal dominant manner. Each child of an individual with HNPCC has a 50% chance of inheriting the mutation. Most people diagnosed with HNPCC have inherited the condition from a parent. However, not all individuals with an HNPCC gene mutation have a parent who had cancer. Prenatal diagnosis for pregnancies at increased risk for HNPCC is possible.

HNPCC is also known as the Lynch syndrome after Dr. Henry Lynch at Creighton University in Omaha, Nebraska. HNPCC includes the Muir-Torre Syndrome and Turcot Syndrome.