A new genetic test makes it possible to detect people at risk and to personalize the strategy to fight against Lynch syndrome, the most frequent form of hereditary colorectal cancer.
An international team of researchers has developed and validated a new tool to identify the genetic changes responsible for Lynch syndrome. These results were published in the journal Genetics in Medicine.
Lynch syndrome, also called “hereditary non-polyposis colorectal cancer”, or HNPCC (hereditary non-polyposis colorectal cancer), is the most common form of hereditary colorectal cancer (with a cumulative risk at age 70 of 70 to 80%) . It is possible for a person with Lynch syndrome to also develop other cancers outside the colon (endometrium, ovary, small intestine, stomach, biliary tract, urinary tract).
Reduce anxiety about disease risk
This groundbreaking study was led by Sean Tavtigian, Professor of Oncology at the University of Alberta (Canada). “Correctly identifying the genetic changes responsible for a disease is of fundamental importance in clinical care”, believes the scientist. “This approach could prolong patients’ lives, reduce anxiety about disease risk and use health care dollars more efficiently,” he adds.
Quick and precise, the laboratory test, called CIMRA (Cell-free in vitro MMR Activity), improves the classification of genetic variations whose significance is uncertain in Lynch syndrome. “We estimate the accuracy of this tool to be around 97%, making it suitable for clinical use,” continues Sean Tavtigian.
Colonoscopic monitoring
The genes whose alteration is associated with the existence of a lynch syndrome are: MSH2, MLH1 and MSH6, in decreasing order of frequency, in 35%, 25% and 2% of cases respectively. The anomaly affects the genes that control the repair of errors occurring during DNA duplication, at the time of cell division. No genetic alteration is identified in approximately one-third of lynch disease cases.
Colonoscopic monitoring is offered to people carrying a constitutional mutation of the MSH2, MLH1 or MSH6 gene, from the age of 20. Annual gynecological monitoring in women after 30 years is recommended. *
*Source: orpha.net
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