deCODE Scientists Discover Another Set of Common Genetic Variants Linked to Risk of Breast Cancer

Scientists from deCODE genetics today report the discovery of two common single-letter variants (SNPs) associated with risk of estrogen receptor-positive (ER+) breast cancer. More than 60% of the general population carry at least one copy of the risk variant of the most important SNP, and women who have inherited the variant from both parents are at approximately 50% greater risk of developing ER+ breast cancer than women who have not inherited the variant. The second variant is located near the first and occurs only in tandem with it, adding slight risk of the disease. Although these variants confer modest risk, they are so common that they are estimated to account for approximately 11% of breast cancers overall.

With this latest discovery, the genetic factors underpinning a very significant proportion of inherited risk of ER+ breast cancer have now been elucidated. Common variants previously discovered by deCODE are together involved in an estimated 25% of ER+ breast cancers.

deCODE made today's discovery through the analysis of genotypic data from a total of nearly 40,000 patients and control subjects from five countries. deCODE gratefully acknowledges the participation of the patients and researchers who took part in this study.

The paper, 'Common variants on chromosome 5p12 confer susceptibility to estrogen receptor-positive breast cancer,' is published today in the online edition of Nature genetics, at www.nature.com/ng.

A Smoking Gene: deCODE Scientists Identify a Genetic Variant that Confers Nicotine Dependence

Scientists from deCODE genetics have identified a clear link between one genetic variant and susceptibility to nicotine dependence and will publish their results in the April 3 issue of Nature. Moreover, in part because of its impact on smoking behavior, each copy of the risk variant of this SNP confers an approximately 30% increase in risk of lung cancer and a 20% increase in risk of peripheral arterial disease (PAD), a common and debilitating constriction of the arteries to the legs.

deCODE scientists came upon the genetic variant by closely examining the genetic makeup of more than 10,000 smokers. They then followed up with an analysis of 32,000 patients and controls from Iceland, New Zealand, Austria, Sweden, Italy, the Netherlands and Spain for lung cancer and PAD, two common diseases strongly associated with smoking.

Kari Stefansson, deCODE CEO, expressed the importance of the discovery: "These findings provide an example of the power of human genetics for shedding light on the most complex health challenges. Not only have we made a convincing link between a single genetic variant and a behavioral disorder - greater smoking quantity and addiction to nicotine - but also demonstrated how this risk factor translates into risk of lung cancer and PAD."

Stefansson also pointed out that deCODE's genetic profile service, deCODEme, will test for the gene immediately.

Details of the smoking gene study, which was funded in part by the European Commission, and from the National Institute of Drug Abuse of the U.S. National Institutes of Health, are available at www.nature.com.

deCODE Obesity Study Sheds Light on how Genetics Affects Risk and Onset of Common Diseases

In a paper published online today in the journal Nature, a team of deCODE scientists detail a major mechanism through which genetic factors contribute to major public health problems.

In its work on the inherited components of dozens of common diseases, deCODE has discovered gene variants that significantly affect individual susceptibility or protection against disease. In the common forms of these conditions - such as obesity, type 2 diabetes and cardiovascular diseases - deCODE has previously shown that genetic variants confer increased or decreased risk by upregulating or downregulating the activity of major biological pathways.

In today's paper, the deCODE team and collaborators from Merck demonstrate one of the principal ways in which the activity of biological pathways is functionally perturbed in a quintessentially complex condition: obesity.

Kari Stefansson, CEO of deCODE, put the study into context: "One of the observations we have made in our work on the isolation of disease genes is that the genetic risk of common diseases is often conferred by variations in the sequence of the genome that affect expression of genes. Hence, one of the ways to approach the study of common diseases is through the analysis of gene expression. This paper provides a substantial contribution towards the understanding of gene expression in man and one example of how it can be used to expand our knowledge of one disease, namely obesity."

deCODE Discovers Fourth Set of Prostate Cancer Risk Variants, Now Integrated into deCODEme™

deCODE scientists today announced the discovery of two more genetic variants linked with increased risk of prostate cancer. These variants have been integrated into the prostate cancer disease module in deCODEme™, and subscribers can check for them in their updated personal profile.

These latest SNPs are the fourth set of variants that deCODE has linked to prostate cancer risk. They are single-letter variations in the genome - SNPs - located on chromosome 2 and on the X chromosome. The SNPs confer relatively modest increases in risk - of approximately 20% and 15% per copy carried, respectively - but because they are also quite common they are each believed to contribute to about 5% of prostate cancer cases. They were found through the analysis of 300,000 SNPs in 23,000 Icelanders in deCODE's prostate cancer studies, and then confirmed in an analysis of more than 15,500 individuals from seven different cohorts from Europe and the United States.

Published studies by major academic research groups in the United States and Europe have over the past month provided strong validation of the role of the other common risk variants, on chromosomes 8 and 17, discovered by deCODE in 2006 and 2007. Altogether, the prostate cancer risk variants now included in deCODEme™ contribute to more than 50% of all cases of the disease. Because of these variants, 10% of men are at twice the risk and 1% of men are at three times the risk of the disease in the general population.

For those subscribers who believe they should consider having a DNA-based diagnostic test for prostate cancer risk variants that they can use with their doctor, deCODE has also just launched deCODEPrCa™, the first such test aimed at understanding individual risk of the disease.