Sunday, January 29, 2012

Common genetic variance linked to many diseases

When it comes to genetics, it is often said that we are all the same, but every individual is genetically unique. Our DNA is about 99,9 percent identical, and even between humans and monkeys there is barely any difference. Yet, for every one of the 3 billion pieces of our genome, there are variants. It means that every human being has a unique genome: no other individual is genetically identical. When it comes to genes, there are a lot of variants in the human population. While the differences are usually not that big, there can be some functional differences. It also means some varieties are linked to an increased risk of disease: one of the variants may not function as well as others. Scientists from the Institute for Molecular Medicine Finland performed a genetic analysis on many commonly found genetic variants, and found that many of them are associated with an increased risk on disease.

The Finnish researchers performed a rather large study. 8330 participants underwent a genome-wide association study, which means all of their DNA was scanned. Their goal was to associate certain common genetic variations, 7.7 million in total, with biomarkers that are often found in disease. A biomarker is a molecule that, when its levels are measured, indicates the presence or absence of disease. In their study, the scientists looked at 117 known biomarkers, which were either lipids, proteins, amino acids, or other molecules.

After linking all the results together, the scientists found 31 genetic regions to be associated with increased levels of biomarkers. These regions were found to be involved in certain metabolic processes, such as handling the amount of circulating cholesterol, or affecting processes that are commonly found in cardiovascular disease and diabetes. It means that if you possess a bad variety of one of these regions, the risk on developing such a disease increases. Additionally, it was shown that genetic variants linked to increased levels of biomarkers have a large degree of heritability.

When you analyse a large number of people genetically to assess whether you can find an increased risk of something, and you look at 7.7 million parts of the DNA, then you're bound to find something. Still, it makes sense that some of us are inherently better at preventing disease. After all, we're all born with a different edition of the genetic code. If you know which variant you possess and the associated increase in risk of developing a certain disease, you can take countermeasures, for example by changing your lifestyle. Because we are talking about common varieties, you need to perform large studies to find links to diseases, as the differences are small. Biomarkers have proven to be a handy tool, because they indicate risk, and function as an indirect measurement. You do not have to wait until the disease manifests, because that takes longer, and many other factors come into play. It means the effect could possibly be too hard to measure. All in all, it is an interesting result, because it highlights how seemingly normal parts of the DNA affect your body.

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