DeCODEING ICELAND’S DNA

by mattfedoruk

(August 2003)

Where’s the best place to hunt for genes that underlie cancer and heart disease? CEO Kari Stefansson and his colleagues at deCODE Genetics believe the relative homogeneity of Iceland’s population should make it a good place to investigate the genetics factors involved in human disease. DeCODE hopes to profit by selling their knowledge to pharmaceutical companies, which can use it to develop diagnostic tests and drugs. Based in Reykjavik, deCODE’s product is genetic information linked, anonymously, to medical records for the country’s 275,000 inhabitants. Isolated populations provide a relatively simple genetic background with which one can investigate the genetics of disease. Because so many Icelanders share the same ancestors, and because family and medical records are so thorough (the national health service began in 1915), it should be easier to identify a genomic locus linked to disease among Icelanders than it would be in an outbred population. They have already proved their worth in studies of conditions caused by single defective genes, for example, rare hereditary conditions, including forms of dwarfism, epilepsy, and eye disorders. DeCODE has also initiated projects in 25 common diseases including multiple sclerosis, psoriasis, preeclampsia, inflammatory bowel disease, aortic aneurism, alcoholism and obesity.

What makes the icelandic genome ideal for study?

• Iceland’s population is relatively small – about 275,000 people.
• Detailed individual medical records have been maintained by public health services since 1915.
• Genealogy is an integral part of the culture — 80% of all Icelandic people who have ever lived can be traced on family trees. There is an advantage to having genealogical data when studying a group’s DNA, e.g. a list of people with a common disease can be run through the genealogical database to look for clues to genetic and environmental causes for the disease.
• The country is isolated geographically, with little migration from other places ever since a few hundred Vikings and some Celts arrived almost 1200 years ago. In addition, over the centuries, a series of disasters such as plague and famine, have minimized the opportunity for new genetic input into the country’s gene pool.
• Some scientists believe that the homogeneity of a population such as Iceland makes the search for genes associated with disease a simpler task. deCODE has already discovered variations in the Icelander’s genome that may indicate susceptibility to multiple sclerosis, hereditary hand tremors, and osteoarthritis.

Analyzing the Genome

While only about 0.1% of your DNA differs from that of any other individual, this small difference can have a major impact on your health, by deciding your susceptibility to disease and your response to drugs. DeCODE is involved in tracking down those crucial differences by comparing chromosomes from different people and looking for distinguishing DNA variants. These include specific DNA sequences known as microsatellite markers and single nucleotide polymorphisms (SNPs) – changes in one DNA letter. A variation of just one of these A, C, G, or T’s between people is an SNP (it is truly an SNP when the frequency is >1%). Between the two of us, we have about 1 SNP for every ~1,500 nucleotides. Scientists estimate that there are between 2 and 3 million SNPs in the human genome. SNPs are responsible for some of our phenotypic differences, and possibly what drugs will affect each of us and what diseases we might be susceptible to as a result of slightly different isoforms (protein variants) between us. At each SNP location there can be four possible variants (A, C, G, or T). At present, SNPs are genotyped by two main methods. In the “chip approach”, fluorescently labeled complementary DNA or cDNA sequences that bind to a particular SNPs are attached to a solid surface, usually a glass slide, which is then exposed to the sample DNA. The SNPs in the sample are then identified from the resulting fluorescence pattern on the DNA chip. Once the chips have been made, this method is very efficient as it allows large numbers of SNPs to be analyzed at once. The alternative is to use mass spectrometry. The sample DNA is treated so that the nucleotides in certain SNPs are substituted for nucleotides bearing addition chemical groups. The SNPs are then detected by analyzing the molecular mass of fragments of the DNA. Only a small number of different SNPs can be genotyped at one time, but the analysis is extremely fast, and new SNPs can be incorporated into a study very easily. In their current research, working together with the new DNA sequence map provided by the Human Genome Project, deCODE has been able to pinpoint about 5000 microsatellite markers and over two million SNPs on the genome sequence. DeCODE has also discovered that the frequency of homologous recombination – the process in which maternal and paternal chromosomes exchange DNA as sperm and eggs are formed, can vary greatly between women. This suggests that environmental factors might change how quickly chromosomes evolve in different countries, or that genetic factors might affect that change in populations.

Figure 1. A Single Nucleotide Polymorphism – Small changes in DNA sequence such as these can have significant phenotypic effects inclyding drug response and disease suceptibility

Genes For Sale

According to some however, Iceland is selling its soul to the devil, and that devil is DeCODE. Icelandic Parliament’s decision to grant deCODE privileged access to medical records has angered some citizens, who object to their country’s gene stock being used to profit a single company. DeCODE has promised in turn to make any treatment or diagnostic test developed from their research available free of charge to Icelanders during the life of the patent. Ethical and moral principles aside, deCODE continues to look for commercial partners for its collaborative studies.

Why is there opposition to the project?

• The database could violate personal privacy, providing easier access to health information that may be abused. An individual’s information is encrypted, deCODE maintains, but codes can be broken. Most experts who reviewed the project’s privacy measures consider the information in the database personally identifiable.
• The plan presumes the consent of all Icelanders. A person may opt out of the database at any time but any data that has already been entered about this individual will not be removed. This person then becomes the subject of research without consent. In addition, the law does not require that Icelanders be told what kind of research will be done with their personal data.
• There is a possibility that the results of the project may have adverse effects, such as medical stereotyping. For example, research into one of the diseases financed by Hoffman-LaRoche is schizophrenia, a mental disorder. If a significant percentage of the population were found to have schizophrenia, would health insurers jump to the conclusion that anyone with an Icelandic heritage anywhere in the world is predisposed to the disease?
• As sole licensee, deCODE has a monopoly on the data. The database belongs to the national health system managed by the government but deCODE has the right to commercialize the data for 12 years. Legislation even assures deCODE that access to the data cannot be granted if it harms the financial interest of the company.
• deCODE plans to market its information for a fee to interested parties, including pharmaceutical and health insurance companies. For example, the arrangement with Hoffman-LaRoche for 12 diseases effectively blocks anyone else from studying these diseases in Iceland.
• Free medications for specific conditions have been promised to Icelanders. However, the gesture comes with a stipulation — deCODE and its business partners must first acknowledge that the medications were developed as a result of the database.
• The government has touted the national economic benefits to be gained from the partnership with private enterprise. Although deCODE pays the government an annual license fee, this fee covers only the costs of the database and administration.
• Both deCODE and the government have speculated that biotechnology jobs in Iceland will increase because of the project. They failed to add that in this internet-connected world, scientists could work with the data on a computer in any location. There has been no influx of scientific research or pharmaceutical facilities to Iceland since the project began. However, there are a few jobs available at deCODE.

  References:

  1. Abbott, A. Nature. 406, 340-342 (2000).

  2. de la Chapelle, A. J. Med. Genet. 30, 857-865 (1993).

  3. Marshall, E. Science. 278, 566 (1997).Science

  4. DeCode Genetics – www.decode.com

  5. Mapping the Icelandic Genome – sunsite.berkeley.edu/biotech/iceland/

  6. For Sale: Iceland’s Genetic History – link

  7. Spencer, R. The Journey of Man. Princeton. 0-691-11532-X. 256 pp. (2003).

  Editor’s note: As of April 2004, Iceland’s government ruled that the project be discontinued deeming it an invasion of privacy rights. Abbot, A. Nature. 429, 118 (2004).

  (Art by Jen Philpott)