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How genetic contributions to common diseases are found - genetic association studies
What are genetic association studies?
Association studies are used to identify DNA profiles from hundreds to thousands of people with a known and common medical condition, for example diabetes. These DNA profiles are compared with those from a second (control) group that does not have diabetes. Any differences in terms of DNA profiles between these groups imply that a segment of DNA (or even an actual gene) might be the cause of the diabetes.
These findings may be reported in the media as “New gene found that causes diabetes”. However, this is only a superficial assessment of what the research study has actually shown. All that can usually be said from association studies is that the DNA change might somehow be implicated in the development of the disease. It does not mean that every person with that particular form of the gene or the DNA segment identified will get the disease. More work is needed to confirm the result, and show that the association has functional significance. At best, in diseases like diabetes, finding a new gene provides a risk factor rather than a direct causative link.
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Will genetic association studies tell me anything about my own personal health?
In most cases, the answer is no. Association studies often relate to what are called multifactorial disorders in which many genes and other contributors such as the environment are likely to play a role. So, the information from a single gene for any particular individual will have limited practical application.
Association studies rely on statistical analysis and so errors can also occur. Initial studies are often reported in the media, but subsequent studies (particularly those that do not agree with the initial results) are less likely to hit the headlines. This can give a distorted view of the value of these types of studies. One should always ask if the study has been replicated or confirmed by others.
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What should I think when I hear that another gene important for human health has been found?
Any new finding of a link between DNA and disease is an important step for advancing medical research and ultimately the community’s health. However, it is always wise to ask questions, consult a health professional who understands these types of studies, and not immediately accept every new report.
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