deCODE Genetics shows the precision of population-scale sequencing projects

June 16, 2015

deCODE Genetics CEO Kari Stefansson recently announced that “We have insights into all living, and some dead, Icelanders… At the push of a button, we could find all the women with mutations in the BRCA2 breast cancer gene.” Mutant BRCA1 and BRCA2 genes are highly predictive of breast and other cancers and women with such mutations, such as actress Angelina Jolie, often choose to undergo mastectomies and other surgeries to reduce their risk. However, many women do not know that they are carriers. deCODE Genetics’ extensive genetic screening within the Icelandic population, coupled with strong genealogical records, means that deCODE Genetics could now identify carriers of mutant BRCA2 genes, not only amongst those in the study, but in the entire population of Iceland.

The challenge is that deCODE Genetics cannot tell any of them. This means that at least 724 women are unaware of their risk of developing breast or ovarian cancer, and at least 360 men are unaware of their risk of developing prostate cancer, as calculated in the Nature Genetics editorial accompanying a slew of recent papers from deCODE Genetics. As is typical with clinical research studies, participants were guaranteed anonymity and therefore researchers are ethically prevented from conveying these research results back to the participants. However many feel that it is equally unethical not to tell them. Because of the genealogical records, the BRCA2 status of almost every Icelander can be predicted, bringing the company’s dilemma beyond those in the study group to the entire population of Iceland.

This dilemma will not be unique to Iceland as many countries are conducting large scale population genetics studies, including UK’s 100,000 Genomes Project and US President Barack Obama’s plan to sequence the genomes of one million U.S. citizens. The dilemma of returning results to research participants can be resolved with revised consent agreements for study members. For example, those signing on to the Ontario Health Study must agree that the study team can contact them if an unexpected discovery was made that could significantly affect their health.

This does not resolve the problem when results can be extrapolated beyond the study group to the general population. In Iceland, the discussion may now move into the public realm and as such it will be interesting to see how its citizens respond to this new, important and very personal information.

By: Kathryn Deuchars, Director, Ontario Personalized Medicine Network