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A Mutation Discovered in Iceland that Increases Risks of Osteoporosis and Certain Cancers

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Nature Published Study Illustrates Value of Big Data Research Methods

deCODE genetics (an Amgen subsidiary) and Illumina, global leaders in analyzing and understanding the human genome, together with scientists from the National Hospital of Iceland and the University of Iceland reported today in the journal Nature the identification of a rare nonsense mutation that confers high risk of osteoporosis and osteoporosis related traits. The mutation was also found to dramatically increase the risk of squamous cell carcinoma of the skin, biliary tract cancer, and to promote an imbalance in blood electrolytes and late onset of menarche.

“Our findings strongly implicate LGR4 in the pathogenesis of osteoporosis as well as various other human diseases, including certain cancers,” said study lead author Kari Stefánsson, M.D., Dr. Med., President of deCODE Genetics. “That this one mutation increases the risk of many diseases is not surprising. The mutation impacts an important signaling pathway known as Wnt, that contributes to the function of many cell types.”

In this study, the research team searched for gene mutations-or other variations in the genome-that may have a direct effect on the risk of pathologically low-bone density among a large set of sequence variants.

Using deCODE’s whole genome sequencing of 2,230 Icelanders, 34 million sequence variants were identified and subsequently analyzed against 4,931 persons with low-bone density disease and a large control population. From this approach, the research team discovered the nonsense mutation in LGR4 and its large effect on osteoporosis and osteoporosis related traits.

The effect of the LGR4 mutation on many other conditions was further investigated taking advantage of a large number of human diseases and other traits that are available at deCODE. Through this effort the mutation was also found to increase the risk of squamous cell carcinoma of the skin and biliary tract cancer as well as to cause blood electrolyte imbalance and late onset of menarche.

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May 5th, 2013 at 5:00 pm

deCODE Genetics Discovers Mutation Conferring Protection Against Alzheimer’s Disease and Cognitive Decline in Elderly

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deCODE Genetics, a global leader in analyzing and understanding the human genome, together with their colleagues from the pharmaceutical company Genentech, reported today in the journal Nature the discovery of a variant of the amyloid precursor protein (APP) gene that confers protection against both Alzheimer’s disease (AD) and cognitive decline in the elderly.  The findings also indicate a linkage between age-related cognitive decline and late-onset forms of AD, the most common cause of dementia.

“Our results suggest that late-onset Alzheimer‘s disease may represent the extreme of more general age-related decline in cognitive function,” said study lead author Kari Stefansson, M.D., Dr. Med., CEO of deCODE Genetics.  “Also important, these data support certain Alzheimer‘s disease drug development programs—some of which are already in human clinical trials.”

Alzheimer‘s disease is a progressive neurodegenerative disease associated with the production and accumulation of beta-amyloid peptides produced by cleaving bits off the APP.  While several mutant forms of the APP gene have been linked to early-onset, aggressive forms of AD, there is limited evidence supporting a role for mutations in the gene in the more common late-onset form of the disease.

In searching for low-frequency variants of the APP gene associated with AD, deCODE scientists found a significant association with a mutation in whole genome sequence data from 1,795 Icelanders.  The research team showed that the mutation is significantly more common in the study‘s elderly control group than in those with AD, suggesting that the mutation confers protection against the disease.

The Genentech team then tested these findings using in vitro cellular assays with wild-type APP and APP enriched with A673T, the mutation allele.  Importantly, they showed a significanly reduced production of amyloid beta in cells with A673T.

“Our genetic data  indicate that the mutation is protective against Alzheimer‘s disease,” said Stefansson.  “Our findings and the in vitro work done by Genentech also provide a proof of principle for the idea that blocking BACE1 cleavage of APP may protect against Alzheimer‘s, offering greater confidence to pharmaceutical companies with active BACE1 inhibitor drug development programs.”

Cognitive Decline in the Elderly

To study the assocation of the protective mutation with general cognitive decline, the research team examined the frequency of the mutation in the original Icelandic control group of those cognitively intact at age 85.  The team found an enrichment of the mutation in this group, consistent with its protective effect against AD.

Extending this work further, the team investigated cognitive function using a seven-category test in carriers of the mutation and non-carriers in the age range of 80 to 100 years old.  The research team found a statistically significant difference between carriers and non-carriers, with the carriers of the mutation having a score indicative of better-conserved cognition.  After removing known AD cases, the team again found that carriers had better cognitive function, suggesting that the mutation extends its protective effect to the elderly in general.

“The implication of these data is that general cognitive decline and late-onset Alzheimer‘s disease share biological pathways,” said Stefansson.  “It also suggests that approaches to treating Alzheimer’s may have benefit to those elderly who do not carry the protective mutation, and do not suffer from AD.”

Alzheimer’s Disease

Alzheimer’s disease, a progressive neurodegenerative disorder, is the most common form of dementia that affects four to eight percent of the elderly population worldwide. The neuropathological features of AD are the presence of extracellular amyloid plaques and intracellular neurofibrillary tangles in the hippocampus and cortical grey matter of the AD brain.

Age-specific prevalence of AD nearly doubles after age 65, leading to a prevalence of greater than 25 percent in those over the age of 90.

deCODE Announces Agreement with Pfizer to Search for Variants in the Human Genome that Confer Risk of Systemic Lupus Erythematosis

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deCODE genetics today announced that it has entered into a research collaboration with Pfizer Inc., the objective of which is to discover sequence variants associated with specific clinical phenotypes related to Systemic Lupus Erythematosis by utilizing deCODE‘s expertise in gene discovery.

deCODE’s discovery capabilities combine its extensive population and genetic resources, including DNA samples and medical data, complete genealogical information, next generation sequencing technology, and deCODE’s proprietary bioinformatics and statistical capabilities. Over the next 18 months, deCODE and Pfizer will work together to analyse the genomes of patients to search for sequence variants that would be useful for understanding drug targets and discovering novel drug targets, that may ultimately lead to tools for patient stratification and companion diagnostics.

“This agreement is a part of deCODE’s ongoing strategy to unleash the value of human genetics,” said Dr. Kari Stefansson, founder and CEO of deCODE, “our research platform allows us to understand the genetic basis of disease and modifiers of clinical phenotypes in actual patient populations; by doing so, we can rapidly move from targets to patient stratification and from there to companion diagnostics.”

The research collaboration will utilize the expertise and capabilities of both deCODE and Pfizer: deCODE’s comprehensive population genetics resources and analytical expertise and Pfizer’s dedication to the application of genomic analysis to the discovery and development of drugs.

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October 12th, 2011 at 6:24 pm

deCODE Genetics, in Collaboration with Academic Colleagues and Illumina, Discovers Two Rare Variants that Affect the Risk of Gout and Serum Uric Acid Levels

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Scientists at deCODE Genetics and academic collaborators from Iceland, Norway, Denmark, the Netherlands and the USA today report the discovery of low frequency variants in the human genome that associate with risk of gout, a common inflammatory arthritis, and serum uric acid levels. The study was done in collaboration with Illumina Inc., and is published today in the online edition of Nature Genetics.

Using Illumina sequencing technology, deCODE scientists determined the sequences of the entire genomes of 457 Icelanders, and identified 16 million single nucleotide polymorphisms (SNPs). Through a combination of SNP genotyping and computational techniques utilizing the extensive Icelandic genealogy, they were able to propagate those 16 million variants into over 40,000 Icelanders, including over 1,200 patients with gout and over 22,000 individuals for whom serum uric acid measurements were available.

The researchers observed a sequence variant in a previously unidentified gout susceptibility gene located on chromosome 19 that has a large effect on serum uric acid levels and gout. The sequence variant is a mis-sense mutation that causes an increase in the level of uric acid by 0.04 mmol/L and a three-fold increase in the risk of gout. Close to 4% of individuals in the overall Icelandic population carry this variant, and ~0.2% of the individuals assessed by academic collaborators in Norway, Denmark, The Netherlands and the United States.

The variant encodes an amino acid change in ALDH16A1, a member of the aldehyde dehydrogenase (ALDH) superfamily, and could motivate further biological studies of this pathway. Other members of the ALDH superfamily have been associated with other clinical phenotypes including alcohol-induced flushing.

Also, at a previously reported locus on chromosome 1, the researchers discovered another novel low frequency variant associating with serum uric acid level and gout. The variant decreases the risk of gout by 50%, and the level of uric acid by 0.05 mmol/L. Approximately 3% of the Icelandic population carry this variant and 1.5% of the European subjects.

For both loci the effect on risk of gout is significantly higher among men than women, but the effect on serum uric acid levels is the same in both sexes.

“This study underscores the importance of whole genome sequencing of well-phenotyped populations. We are pleased that the clinical and genetic resource that deCODE has built enables us to make such discoveries,” said Kari Stefansson, deCODE’s CEO and senior author of the study.

“We are committed to turning discoveries such as this, as well as our recent findings in ovarian cancer and sick sinus syndrome, and our future discoveries, into real benefit for patients,” Dr. Stefansson continued.

Gout is a common inflammatory arthritis caused by urate crystal formation resulting from a high concentration of uric acid in the blood, which is in turn caused by an imbalance in the dietary intake of purines and in the synthesis an excretion of urate. The incidence of gout increases with age and is three times higher in men than in women.

deCODE Discovers Genetic Risk Factor for Sick Sinus Syndrome

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deCODE-genetics-headquarters-in-Iceland

Scientists at deCODE genetics and academic colleagues from Iceland, The Netherlands, Denmark, USA and Illumina, Inc., today report the discovery of single-letter variants (SNPs) in the sequence of the human genome associated with high risk of sick sinus syndrome. The study is published today in the online edition of Nature Genetics.

The study reports a genetic variant in the gene MYH6 that is associated with high risk of sick sinus syndrome in Icelanders. The lifetime risk of being diagnosed with Sick sinus syndrome is about 6% for individuals without this genetic variant but is increased by 12.5 times, to approximately 50%, for those that carry the variant. Sick sinus syndrome is a heart rhythm disorder that is characterized by an inappropriately slow heart rate. It is commonly seen in the elderly and many with Sick sinus syndrome eventually need a permanent pacemaker.

With the aim of searching for sequence variants that predispose to Sick sinus syndrome, a genome-wide association study was performed including 792 Icelanders with Sick sinus syndrome and 37,592 Icelandic controls. The study utilized SNP data from several sources including Illumina SNP chip genotyping as well as whole-genome sequencing of 7 Icelanders with Sick sinus syndrome and 80 Icelanders not diagnosed with Sick sinus syndrome. The whole-genome sequencing data yielded a strong association between Sick sinus syndrome and a rare missense mutation in MYH6 that could not be accounted for by any other sequence variation. MYH6 encodes one form of myosin, a major component of the contractile system of the heart, and was recently associated with the function of the conduction system of the heart by studies from deCODE and others. This is the first time that MYH6 is implicated in the development of heart rhythm disorders.

“This work constitutes our first entry into the study of rare variants in common diseases that confer large risk of disease. It is clear that the risk of common diseases in our society is accounted for by both common and rare variants in the sequence of the genome. We here at deCODE and scientists all over the world have over the past few years discovered large numbers of common variants that confer risk of common diseases. Now we are entering into the era of rare variants that are providing us with clear insights into the pathogenesis of diseases and possibilities of putting together very effective diagnostics” said Kari Stefansson, deCODE’s CEO and senior author of the study.

The paper, “A rare variant in MYH6 is associated with high risk of sick sinus syndrome” is published online in Nature Genetics at www.nature.com/ng and will appear in an upcoming print edition of the journal.

Sick sinus syndrome, or sinus node dysfunction, is a common clinical disorder that is characterized by pathological slow heart rate, sinus arrest and/or attenuated heart rate response to exercise. The syndrome comprises a wide range of electrophysiological abnormalities, including failure of the sinus node and atrial impulse formation or propagation, as well as susceptibility to atrial tachyarrhythmias, particularly atrial fibrillation. Although encountered at any age, Sick sinus syndrome is primarily a disease of the elderly and is often secondary to other cardiac disorders when diagnosed in younger individuals. Symptoms are often intermittent and/or nonspecific and include dizziness, syncope and heart failure. The only effective treatment for symptomatic and irreversible sinus node dysfunction is permanent cardiac pacing, and Sick sinus syndrome remains the most common indication for permanent pacemaker implantation.

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March 4th, 2011 at 6:24 pm

deCODE discovers genetic markers that improve the power of PSA testing for detecting prostate cancer

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deCODE discovers genetic markers that improve the power of PSA testing for detecting prostate cancer

Analysis of four SNPs, in tandem with genetic risk factors detected by the deCODE ProstateCancer™ test, yields substantial improvement in efficacy of PSA screening

Scientists from deCODE genetics and academic colleagues from Iceland, the UK, US, Netherlands, Spain and Romania today report the discovery of a set of single-letter variations in the sequence of the human genome (SNPs) that impact individual baseline levels of prostate specific antigen, or PSA. Testing for PSA levels is the most commonly used screening tool for the detection of prostate cancer. A prostate biopsy is routinely recommended for men with PSA above a certain threshold. However, PSA levels can rise for reasons unrelated to prostate cancer and baseline healthy levels vary substantially between individuals, resulting in many men without cancer being biopsied while cancer in others is not detected. The paper published today demonstrates that analysis of four SNPs can be used to derive a personalized PSA threshold that more accurately identifies those men who are more likely to have a positive biopsy and for whom one should therefore be recommended.

“This is straighforward genetics with direct clinical utility. Detected early, prostate cancer can be treated with near total success. The challenge is to more effectively risk stratify the population, identifying and biopsying those at high risk and with aggressive disease while minimizing the number of negative biopsies we perform. And using the genetics we are improving the sensitivity and specificity of PSA testing. Like virtually every protein in the body, PSA levels vary between individuals according to SNPs that regulate gene expression. The SNPs reported today enable us to personalize PSA thresholds, thereby changing the recommendation on whether to biopsy for a substantial proportion of men. Moreover, the discriminatory power of testing for these SNPs is highest when done in tandem with the SNPs associated directly with risk of the disease measured by our deCODE ProstateCancer™ test. We are working to swiftly incorporate these PSA markers into our testing portfolio,” said Kari Stefansson, CEO of deCODE and senior author on the study.

The paper, entitled “Genetic correction of PSA values using sequence variants associated with PSA levels,” is published today online in Science Translational Medicine and will appear in an upcoming print edition of the journal. The study was conducted in several stages and involved tens of thousands of men with and without prostate cancer. First, more than 300,000 SNPs were analyzed in 16,000 Icelandic men with PSA measurements but who had never been diagnosed with prostate cancer. SNPs that correlated with PSA levels were identified and then validated in a cohort from the UK. These SNPs were then studied in large case-control cohorts from Iceland, the Netherlands, Spain, Romania and the US to establish the association with PSA levels independent of risk of prostate cancer itself. The authors then demonstrated how measuring four SNPs correlated with PSA levels can be used to obtain a personalized threshold for when to biopsy, and that using such thresholds improves the ratio of positive to negative biopsies. The greatest improvement in prediction accuracy was seen when men were tested both for the PSA correction SNPs as well as a panel of prostate cancer risk SNPs detected by the deCODE ProstateCancer™ test.

deCODE and the authors wish to thank the thousands of participants who took part in this study. It was funded in part by grant 202059 (PROMARK) and grant 218071 (CancerGene), both from the 7th Framework Program of the European Union.

deCODEme for “Curious George” – A catalog of published results from the National Human Genome Research Institute

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National Human Genome Research Institute catalog can now be accessed through your deCODEme account

The National Human Genome Research Institute catalog can now be accessed through your deCODEme account

Through your deCODEme account (or the demo account if you are not yet a deCODEme customer) you can access a catalog of published Genome-Wide Association Studies (GWAS) that has been compiled by the National Human Genome Research Institute (NHGRI).

This feature allows you to gain a quick overview of where research on common traits has been showing associations with single nucleotide genetic variations (SNPs).  Users can easily select a disease or trait from a list and a feature track with the corresponding SNPs from the catalog will show up in our Genome Browser.

Many of the associations in the GWAS catalog compiled in August 2009 are included in our Health Watch feature. There are also numerous other associations that our scientists have not included, as they do not fulfill the criteria we set for inclusion in our Health Watch.

The GWAS catalog is presented (see here) simply as it appears on the NHGRI web site and has not been reviewed by deCODE’s scientists. The catalog is provided primarily for educational purposes – for the curious George who wants to look at genome-wide association study results in the context of other information that we provide in our Genome Browser.

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November 19th, 2009 at 3:32 pm

deCODE Discovers New Risk Factors for Prostate Cancer

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deCODEme Prostate Cancer

deCODEme Prostate Cancer

Last night we announced our discovery of four more SNPs linked to increased risk of prostate cancer. At the same time, academic collagues in the US and UK have also found more SNPs. (See article in TIMES ONLINE) All of the well-validated new risk variants will be incorporated into your deCODEme profile in the days ahead.

In the same study we published yesterday, we also conducted an analysis of all well-validated genetic risk factors discovered to date to establish what percentage of men would be at a significantly higher risk than average using these markers. Based upon our ability to swiftly conduct a population-based analysis in Iceland, this analysis demonstrates that about 4% of men are at more than double average risk based upon these risk factors, while just over 1% are at more than 2.5-times average risk.
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Written by Gisli Arnason

September 21st, 2009 at 3:06 pm

deCODE-led Megastudy Finds New Genetic Clues to Causes of Schizophrenia

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deCODE-led Megastudy Finds New Genetic Clues to Causes of Schizophrenia. Findings expand knowledge of the biology of the disease and provide potential new drug targets.

deCODE-led Megastudy Finds New Genetic Clues to Causes of Schizophrenia. Findings expand knowledge of the biology of the disease and provide potential new drug targets.

The largest study of the genetics of schizophrenia ever undertaken has revealed several new common single-letter variants in the sequence of the human genome (SNPs) linked to risk of the disease. The study, by a multinational consortium of scientists led by a team from deCODE genetics, analyzed the genomes of more than 50,000 patients and control participants from fourteen countries. It is published today in the online edition of Nature.

One of the SNPs is located near the neurogranin gene (NRGN) on chromosome 11. NRGN may be a candidate drug target, as it appears to play an important role in regulating both memory and cognition, processes that are often perturbed in schizophrenics. Another SNP is in the transcription factor 4 (TCF4) gene on chromosome 18, which is involved in brain development. Five of the SNPs are located very closely together in the Major Histocompatibility Complex, a region on chromosome 6 densely packed with genes regulating immune response. This lends support to previous research suggesting a possible environmental link between schizophrenia immune response. It has long been known, for example, that a disproportionately large number of schizophrenics are born in the winter and spring, when influenza rates are usually highest. All of the variants found in this study are very common and each is associated with a modest increase in risk.

“Genetics offers a unique window for better understanding diseases like schizophrenia because the brain and cognition are so little understood and so difficult to study. Discoveries such as these are crucial for teasing out the biology of the disease and making it possible for us to begin to develop drugs targeting the underlying causes and not just the symptoms of the disease. One of the reasons this study was so successful is its unprecendented size. Pooling our resources has yielded spectacular results, which is what the participants from three continents hoped for. At the same time, this study underscores the fact that rare variants may well carry a significant part of the genetic risk of schizophrenia, so our next task is to use the ever more affordable sequencing technologies to find more of them,” said Kari Stefansson, CEO of deCODE and corresponding author on the paper.

In the first phase of the study, the deCODE-led SGENE consortium conducted a genome-wide scan of more than 300,000 SNPs in a total of 17,000 patients and controls from England, Finland, Germany, Iceland, Italy and Scotland. The 1500 SNPs with the best signal were then analysed in 11,000 patients and controls from the International Schizophrenia Consortium (ISC) and the European-American portion of the Molecular Genetics of Schizophrenia studies (MGS). Twenty-five SNPs with strong suggestive correlation were then followed up in more than 20,000 patients and controls from the Netherlands, Denmark, Germany, Hungary, Norway, Russia, Finland and Spain. Bringing together the results of different consortia established he association between the total of seven markers on chromosomes 6, 11, and 18 with increased risk of schizophrenia.

deCODE and all of the authors would like to thank the participants who took part in this study and made it possible. The SGENE consortium and its affiliated groups include deCODE genetics, the National-University Hospital in Reykjavik, the University of Aberdeen, the Ravenscraig Hospital in Greenock, the Institute of Psychiatry at King’s College London, the National Public Health Institute in Helsinki, the Ludwig Maximilians University and GlaxoSmithKline’s Genetic Research Center in Munich, the University of Copenhagen, the University of Oslo, the University of Heidelberg, the University of Bonn, the University Medical Center of Utrecht, Nijmegen Medical Center, the University of Verona, the Duke University Center for Population Genomics and Pharmacogenetics and the University of Sichuan, China. Follow up cohorts included those from Aarhus  University, the National Serum Institute, and Bispebjerg and Glostrup hospitals, Denmark; Semmelweis University, Budapest; the Mental Health Research Center of the Russian Academy of  Sciences; the Universities of Valencia and Santiago de Compostela, and the Hospital General Universitario Gregorio Marañón, Madrid, Spain; The Northern Finland Birth Cohort; Karolinska Institutet, Stockholm; Universities of Amsterdam, Utrecht and Maastricht, the Netherlands. The institutions comprising the ISC and MGS can be found in papers published concurrently with the present study in the online edition of Nature.

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July 5th, 2009 at 5:33 pm

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deCODE Discovers a Gene Linked to Risk of Kidney Stones and Osteoporosis

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deCODE Discovers a Gene Linked to Risk of Kidney Stones and Osteoporosis. Findings offer promising target for drugs to better regulate calcium metabolism, are integrated into deCODEme™.

deCODE Discovers a Gene Linked to Risk of Kidney Stones and Osteoporosis. Findings offer promising target for drugs to better regulate calcium metabolism, are integrated into deCODEme™.

A discovery by scientists at deCODE genetics and academic colleagues from Iceland, the Netherlands and Denmark has pointed to a common biological mechanism contributing to both kidney stones and decreased bone mineral density (BMD). About 60% of the population carry two copies of a single-letter variation in the human genome (SNP) on chromosome 21, putting them at roughly 65% greater likelihood of developing kidney stones than those who carry no copies. This single variant may thus account for more than a quarter of the incidence of kidney stones, and in women carriers it is also associated with decreased BMD at the hip and spine.

The study, which involved the analysis of the genomes of some 50,000 patients and controls, is published in the online edition of Nature Genetics and will appear in upcoming print edition of the journal.

The SNP is in the gene encoding claudin 14 (CLDN14), a protein expressed in the kidney and one of a family of membrane proteins that regulate the passage of ions and small solutes between cells. As calcium is a key component both of most kidney stones and of bone, the deCODE team examined the relationship between CLDN14 and the metabolism of calcium. The results suggest that the SNP may be contributing to increased calcium excretion in urine, a major risk factor for kidney stones and also a sign of bone loss.

“This is an exciting finding because it uncovers a highly plausible common biological mechanism leading to two diseases. This offers a potentially attractive new pathway for drug discovery, and the next task is to build on our undertanding of how this SNP increases risk of these diseases and how this pathway could be targeted therapeutically to address this risk. As ever, deCODEme subscribers will see this new variant in their profiles, and we look forward building on this discovery,” said Kari Stefansson, CEO of deCODE.

About kidney stones
Kidney stones are small crystals formed of dissolved minerals, mainly calcium, that form in the kideys. Smaller stones can simply be passed through urination, though larger ones can block the urinary tract, causing considerable pain and bleeding. Kidney stones affect some 5% of women and 10% of men in the industrialized world. Larger stones can be detected with ultrasound screening and broken up to facilitate passage, though the recurrence rate is high.

deCODE would like to thank all those who participated in this study, as well as the collaborating clinicians and scientists from the Landspitali University Hospital in Reykjavik, Iceland, Radboud University Nijmegen Medical Centre in Nijmegen, Netherlands, Nordic Bioscience A/S in Herlev, Denmark and the Center for Clinical and Basic Research A/S in Ballerup, Denmark.

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June 30th, 2009 at 2:39 pm

Who’s afraid of genetic testing?

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As a deCODEyou reader, you have an active interest in how genetics can help to improve personal health and healthcare. If you are a deCODEme subscriber or have taken one of our DNA-based diagnostic tests, you have already followed up on that interest.

Then again, you may not have had your genome analyzed yet. You may simply be interested in taking part in research, having a scan, or simply in keeping up with the latest discoveries.

But whoever you are, your genome is information about you. And at deCODE, we believe that your genome belongs to you. Over the past decade we have worked with hundreds of thousands individuals who have decided to use their genome to advance our gene discovery work, to understand their risk of a certain disease, or who want to have a broad and constantly updated look at their genome through deCODEme. In every case, we think it is the individual who has the right to decide to use their genome and learn about it as they wish.

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Written by Gisli Arnason

April 17th, 2009 at 2:20 pm

Stories from our foremothers: deCODE publishes an unparalleled genetic snapshot of Iceland 1000 years ago

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Iceland was mainly settled by Scandinavian men and women from Irealand and Scotland

Iceland was mainly settled by Scandinavian men and women from Irealand and Scotland

In a paper published today scientists at deCODE genetics present the results of the largest study of ancient DNA from a single population ever undertaken. Analyzing mitochondrial DNA, which is passed from mother to offspring, from 68 skeletal remains from approximately 1000 years ago, the study provides the most detailed look to date at how a contemporary population differs from that of its ancestors. The results confirm previous deCODE work that used genetics to test the history of Iceland as recorded in the sagas.

These studies demonstrated that the country seems indeed to have been settled by men from Scandinavia – the vikings – but that the majority of the original female inhabitants were from the coastal regions of Scotland and Ireland, areas that regularly suffered raids by vikings in the years around the settlement of Iceland 1100 years ago.

Perhaps the most remarkable finding of the study published today is that the gene pool of contemporary Icelanders appears to have evolved rapidly over the intervening thousand years. As a result, the original female settlers are genetically more closely related to the present day populations of Scotland, Ireland and Scandinavia, as well as those of northwestern Europe and even southwestern Europe, than they are to present day Icelanders. This is an important demonstration of a phenomenon known as ‘genetic drift.’ In essence, in any population certain individuals will have more offspring and, by chance and in this case over the course of 35 generations, many more descendants than others. And as a result, particularly in a small population, the genetic variety of the original population can decrease and change over time. In this study only mitochondrial DNA was studied, but the same phenomenon applies to the Y chromosome, which is passed from fathers to sons, and to any other part of the genome. The paper, ‘Sequences from first settlers reveal rapid evolution in Icelandic mtDNA pool,’ is published today in the open-access journal PLOS Genetics.

“This study is a major contribution to the use of ancient DNA studies in tracing the history not just of single populations, but of our species and how we spread from Africa to every corner of the globe. It is the first such study to be large enough to permit meaningful statistical methods to be applied to ancient DNA. We very much hope this will aid and encourage others to follow with large studies in other parts of the world. In this field, as in the genetics of common diseases, we are pleased and proud to be able to put the knowledge we gain in Iceland to work for the benefit of people everywhere,” said Kari Stefansson, CEO of deCODE.

Written by Gisli Arnason

January 16th, 2009 at 1:21 pm

New genetic variants influencing Body Mass Index, Weight, and risk of Obesity

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deCODE scientists have discovered new genetic variants influencing BMI, weight and risk of obesity

deCODE scientists have discovered new genetic variants influencing BMI, weight and risk of obesity

As we all know to well, for decades the scales have been tipping in favor of obesity. The epidemic of obesity in many industrialized countries has been driven by many factors, including easy access to fast food, an increasingly sedentary lifestyle, insufficient daily physical activity. All of this while our genomes have evolved on a background of scarcity, often putting a premium on the ability of the body to turn food into fat and store energy for leaner times. A paper published today by deCODE scientists and academic colleagues from the US and Europe provide a significant advance in our knowledge of the underlying genetics and biology of obesity, providing new information for understanding and addressing obesity and perhaps nudging the scales the other way.
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Written by Gisli Arnason

December 14th, 2008 at 11:00 am

The battle against breast cancer gets personalized

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deCODE Breast Cancer enables women to understand whether they may benefit from more intensive screening, monitoring or preventive drug therapy.

A new genetic test assessing a woman's risk of developing the most common forms of breast cancer has arrived. Can the test, developed by the biopharmaceutical company deCODE, improve the way doctors screen for breast cancer?

Breast cancer kills 40,000 people a year in the U.S. This is about the population of Atlantic City, New Jersey. Imagine, each year an entire city wiped out by breast cancer.

To help fight breast cancer, a new test assessing individual risk has just become available. For women without a clear family history of the disease, the deCODE BreastCancerTM test assesses their personal risk of developing the most common forms of breast cancer. The DNA test, launched by the biopharmaceutical company deCODE, makes it possible to identify those women at significantly higher than average risk, helping doctors use new screening technologies and treatments in a more targeted, personalized and effective manner.

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Written by Gisli Arnason

October 27th, 2008 at 5:35 pm

Your genome, your choice: a buyer’s checklist for genetic tests

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Scientists at deCODE genetics' Genetic Service Facility lab in Iceland

Scientists at deCODE genetics Genetic Service Facility lab in Iceland

The number of companies offering genetic tests to the public is large and growing. But there are vast and very real differences in the quality, purpose and price of testing services out there. So how do you tell the difference between them? And how do you decide which to use?

Knowing what you want

First and foremost, you need to think about what sort of information you hope to gain from your genome and how accurate you want the results to be. Are you taking the test only for fun, perhaps hoping to talk about your results on Facebook? Read the rest of this entry »

Written by Gisli Arnason

September 17th, 2008 at 5:20 pm

deCODE and Radboud University discover common variants in the human genome conferring risk of bladder cancer

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Urinary bladder cancer is something many people have never heard of. But it is the sixth most common form of cancer in the United States, and its environmental risk factors include exposure to toxic chemicals, including some used in industrial processing as well as cigarette smoke. Genetic factors also play a role and may help to elucidate how bladder cancer starts and develops.

Today, deCODE’s cancer group and colleagues at Radboud University in the Netherlands report the discovery of two single letter variants (commonly referred to as SNPs) in the human genome that confer increased risk of bladder cancer. Both are common, and 20 percent of people of European descent carry two copies of the highest impact SNP, located on chromosome 8q24. That puts them at about 50 percent higher likelihood of developing bladder cancer than people who do not carry the variant.

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Written by Gisli Arnason

September 14th, 2008 at 5:00 pm

Not all genetic tests are created equal

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Here are a few thoughts on Nic Fleming’s piece on personal genome scans, of which one was our own, deCODEme:

Our genomes are all remarkably similar. And so it is the differences that are most interesting and important, and that make us who we are.

The same can be said of genetic testing services. We at deCODE were not at all surprised that Mr. Fleming found that he got some varying results from the three genome scans that he tried. Indeed we would be surprised (and more than a little dismayed) if he hadn’t. Analyzing the genome – accurately detecting which genetic markers individuals have at specific points in the genome, and correlating these variations with risk of a range of common diseases – has been our bread and butter for well over a decade. Read the rest of this entry »

Written by Gisli Arnason

September 12th, 2008 at 2:33 pm

Evidence of genetic links to schizophrenia

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deCODE genetics laboratory staff working on genetic research

deCODE and SGENE Consortium Discover Deletions in the Human Genome Linked to Risk of Schizophrenia

Findings may provide the foundation for a test to complement standard clinical diagnosis, potentially enabling earlier intervention and treatment

A team of scientists led by deCODE genetics has discovered evidence of three rare deletions in the human genome that confer a greater risk of schizophrenia. This discovery shows that individuals who have one of these deletions may be up to 15 times more likely to develop schizophrenia than the population at large. See “Large recurrent microdeletions associated with schizophrenia” which appeared this afternoon in Nature (www.nature.com)

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Written by Gisli Arnason

July 31st, 2008 at 4:26 pm

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

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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 up-regulating or down-regulating 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.”

Written by Keith Hayward

March 16th, 2008 at 2:45 pm

Posted in Genetic Research

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