The best genetic test to determine hereditary cancers

The best genetic test to determine hereditary cancers.


Carriers of harmful variants of the SDHD or SDHAF2 genes have a very high risk of developing certain cancers in their lifetime, but only if the defective gene is inherited from the father. If it is inherited from the mother, the patient is not at increased risk. Those at risk must undergo regular lifelong screening and testing to identify cancers early. The new test confirms the presence of a genetic variant predisposing to cancer and is able to determine whether the variant was inherited from the mother or the father  an understanding that has not been possible until now. The study was led by Vahid Akbari and Dr. Steven Jones of the Canadian Michael Smith Genome Sciences Center (GSC), and by Vincent Hanlon and Dr. Peter Lansdorp of the Terry Fox Laboratory of the BC Cancer Research Institute (Vancouver). 



“Being able to assign parent of origin to cancer variants allows us to quickly identify  other members family members who may be at risk,” says Dr. Kasmintan Schrader, co-medical director of the Provincial Hereditary Cancer Program at BC Cancer, professor of medical genetics at the University of British Columbia (UBC), and co-author of the study. “Allowing us to focus on just one side of the family will help us save lives by focusing on prevention efforts. This new approach will eliminate the unnecessary psychological burden of testing family members on the other side who are not at increased risk and reduce the need for clinical counseling by focusing resources on identifying and supporting those that they are really at risk.”



Dr Steven Jones, co-director of the Genome Sciences Center and professor of medical genetics at UBC, adds: ‘The approach was made possible by new long-read sequencing technology, which can not only sequence DNA but also identify subtle functional alterations”. “All of our chromosomes have signs that indicate whether the chromosome comes from our mother or our father,” explains Dr. Louis Lefebvre, associate professor of medical genetics at UBC and co-author of the paper. “The challenge is that out of the three billion base pairs that represent our genome, only about 190 small regions contain these parental marks.” The technology developed by Dr Lansdorp has provided the final missing piece, allowing these small regions to be linked to entire chromosomes.

 This new test could eliminate a lifetime of unnecessary hospital visits and the psychological burden of increased cancer risk.



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