deCODE You

Scientists at deCODE Genetics and academic collaborators from Iceland, the USA, The Netherlands and Spain today report the discovery of variants in the human genome that associate with levels of thyroid stimulating hormone and risk of thyroid cancer. The paper ‘Discovery of common variants associated with low TSH levels and thyroid cancer risk‘ is published today in the online edition of Nature Genetics.

Using data obtained by applying both Illumina whole-genome sequencing technology and Illumina SNP chip technology, deCODE’s scientists performed a genome wide association study on levels of thyroid stimulating hormone (TSH) in 27,758 Icelanders. 22 SNPs with genomewide significance were discovered, of which one, rs965513 had previously been shown to associate with thyroid cancer. The remaining 21 SNPs were genotyped in 561 Icelandic thyroid cancer cases and 40,013 controls. Variants suggestively associated with thyroid cancer were then genotyped in an additional 595 non-Icelandic cases and 2,603 controls.

After combining the results, three separate variants on chromosomes 2q35, 8p12 and 14q13.3 were shown to associate with risk of thyroid cancer, conferring an added risk of 30 – 100%, compared to the general population. These variants were also found to associate with low levels of TSH, a key regulator in the biology and endocrinology of the thyroid gland.

“This study underscores the important role that the genetics of diversity in normal physiologic function can play in understanding the risk of disease. To date, the at-risk alleles of all the variants that confer risk of thyroid cancer associate with decreased serum levels of TSH, suggesting that the primary disorder in non-medullary thyroid cancer is an endocrine one, characterized by decreased concentration of TSH,” said Kari Stefansson, deCODE’s CEO and senior author of the study.

Thyroid Cancer is a malignant thyroid neoplasm, which can be treated with radioactive iodine or surgical resection of the thyroid gland. The contribution of genetics to the risk of thyroid cancer is greater than to any other cancer. Thyroid cancer is classified into four main histology groups: papillary (PTC), follicular (FTC), medullary (MTC), and undifferentiated or anaplastic thyroid carcinomas. The great majority of malignant thyroid tumours are nonmedullary, either PTC (80–85%) or FTC (10–15%).

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.

Scientists at deCODE Genetics and academic collaborators from Iceland, The Netherlands, Spain, Denmark, Germany, Sweden, the USA, the UK and Romania today report the discovery of a variant in the sequence of the human genome associated with risk of developing basal cell carcinoma of the skin (BCC), as well as prostate cancer and glioma, the most serious form of brain cancer.  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 for use in this study.

The researchers discovered a single letter variant located in TP53, a gene known to play a central role in tumor biology and for accumulating so called somatic mutations, during the development of cancer in patients.  Until now, however, individuals who are born with defective copies of the gene (germline variants) have been found extremely rarely, only in families with cancer predisposition syndromes, Li Fraumeni syndrome (LFS) and Li-Fraumeni-like syndrome (LFL). The variant found in the present study is an unusual type of mutation that appears to affect the way the gene’s messenger RNA is processed; the messenger RNA in patients with the mutant TP53 gene appears to lack proper termination and polyadenylation.

This is the first evidence of a germline variant in TP53 associated with cancer predisposition beyond LFS and LFL. While the mutations causing LFS and LFL syndromes are very rare (occuring 1:5,000 to 1:20,000 births), the variant described in this paper occurs in ~ 1 in 25 individuals in Iceland, and at comparable frequencies in US and UK populations.

“This mutation is one of a growing number of deCODE discoveries of relatively low frequency sequence variants with large effect,” said Kari Stefansson, deCODE’s CEO and senior author of the study.  “The discovery of such variants is made possible through the breadth and quality of the data that the Icelandic population provides.”

Dr. Stefansson emphasized, “We will, together with our collaborators, including Illumina, extend ourselves to turn this discovery into benefit for patients and those at risk of cancer.”

BCC is the most common cancer in people of European ancestry. Sun exposure is the primary risk factor for BCC, but genetic predisposition also plays a substantial role.   Until now, no mechanistic causal connection between cancers as diverse as BCC, prostate cancer, glioma, and colorectal adenoma was known.

The paper, “A Germline Variant in the TP53 Polyadenylation Signal Confers Cancer Susceptibility” is published online in Nature Genetics at www.nature.com/ng and will appear in an upcoming print edition of the journal.

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.

Audio link:  Dr. Kari Stefansson interviewed on BBC WORLD. BBC

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.
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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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Reykjavik, ICELAND, December 8, 2008 – deCODE genetics (Nasdaq:DCGN) today announced the discovery by an international consortium of scientists from deCODE and major European and US academic institutions of a single letter variation in the human genome (SNP) that is associated with increased fasting glucose levels and risk of type 2 diabetes (T2D). deCODE will employ its CLIA-registered genotyping laboratory and existing testing platform to swiftly integrate the finding into its deCODEme™ personal genome scan, and to assess the addition of this new variant to the company’s deCODE T2™ reference laboratory test for assessing individual risk of type 2 diabetes.
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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 »

On Sunday, August 17, deCODE published a new statistical method for increasing the information that can be derived from high-density genotyping, leveraging the genotypic data the company has already generated
on tens of thousands of participants in its gene discovery programs. In the above video, CEO Kari Stefansson, the company’s head statistician Augustine Kong, and Chief of Communications Edward Farmer talk about how this method works and why it may help deCODE to find rarer variants conferring risk of common diseases.

Link: Read abstract in Nature Genetics

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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The second part of NBC Nightly News coverage of deCODE genetics and the genetic research conducted with the help of the Icelandic nation. Bazell continues to look at the company he sees as being at the cutting edge of genetic research.

A look at deCODE, the biotech company in Iceland that is researching genes for common conditions like heart disease, stroke and cancer. Sue Herera interviews NBC’s Robert Bazell on his coverage of deCODE and discusses the scientific, pharmacological and commercial implications of genetic testing.

Originally broadcast July 22, 2008.

Link: Watch the interview.

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.

Link: Read the paper, ‘Common variants on chromosome 5p12 confer susceptibility to estrogen receptor-positive breast cancer’, in Nature Genetics