Reykjavik, ICELAND, 23 July 2010 – In a paper published today in PLoS Genetics, a deCODE-led team demonstrates an effective approach for making genetic risk factors discovered on one continent fully relevant to people of various continental ancestries. The strategy, called ancestry-shift refinement mapping, was in this case used to replicate a sequence variant associated with risk of breast cancer discovered in Han Chinese in Shanghai. When tested in women of African and European descent, the SNP found in Shanghai, the T allele of rs2046210, was not found to confer any substantially increased risk.

The deCODE team resolved this problem by identifying other SNPs highly correlated with rs2046210 in Han Chinese, and then identified which of these might be used to tag the same risk in women of African and European origin. Through the analysis of these SNPs in some 20,000 patients and controls from breast cancer studies among African and European women, they homed in on rs9397435, which is also located on chromosome 6q25 near the gene encoding the estrogen receptor α. The African and European women with one copy of the at-risk version of this SNP were found to be at approximately 15% greater risk of breast cancer, similar to the risk conferred on Chinese women by rs2046210. The paper, “Ancestry-shift refinement mapping of the C6orf97-ESR1 Breast Cancer Susceptibility Locus,” is avalaible at www.plosgenetics.org.

This strategy underscores the fundamental observation that common genetic risk factors and the biological pathways they affect are most often relevant to people around the world. But the frequency of specific risk variants – and other variants or markers that tend to associate with them – often varies from one continent to another. deCODE’s ability to address this variability is important for swiftly and effectively making discoveries in one part of the world relevant to the people everywhere. Moreoever, though gene discovery has been thus far largely concentrated in the United States and Europe, discovery teams in other parts of the world are making a growing contribution to our understanding of the genome. Thus it is now imperative not only to be able to make discoveries in populations of European origin relevant to people on other continents, but to translate the relevance of discoveries wherever they are made, to the benefit of all.

About deCODE

Headquartered in Reykjavik, Iceland, deCODE genetics is a global leader in analyzing and understanding the human genome. Using its unique expertise and population resources, deCODE has discovered key genetic risk factors for dozens of common diseases ranging from cardiovascular disease to cancer. deCODE employs its capabilities to develop DNA-based tests and personal genome scans to better understand individual risk and empower prevention and provides comprehensive genotyping, sequencing and data analysis services to companies and research institutions around the globe. Visit us on the web at www.decode.com