New Screening Protocol Identifies More Case of Lynch Syndrome
A new way to select patients for further testing may increase detection of Lynch syndrome, a disorder that predisposes people to developing colorectal cancer at a young age.
Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is caused by mutations in DNA mismatch repair genes, the genes that fix errors that occur during DNA replication.
Kristina Lagerstedt Robinson, Ph.D., of the Karolinska University Hospital in Stockholm, and her colleagues selected a group of 285 families who had been referred to the Karolinska University Hospital for genetic counseling between 1990 and 2005 because they were at high risk for HNPCC. From those families, 112 patients were screened for mutations in mismatch repair genes, often a telltale sign of HNPCC. The screening procedure detected these mutations in 69 patients and also identified at least 57 HNPCC patients, several of whom would not have been screened under current testing practices.
"Although a population-based mutation-screening strategy has the potential to also identify nonfamilial HNPCC patients, more patients will need to be screened," the authors write. "The most important advantage with the family history-based selection process we used is that non-HNPCC families are also identified and can be offered preventive programs."
In a related editorial, Henry Lynch, MD, of Creighton University School of Medicine in Nebraska, and his colleagues discuss the progress that has been made in diagnosing HNPCC, as well as the limitations of current selection for testing.