Friday, 16 November 2007

The Killer in Me

This isn't a confession of homicidal tendencies, but the title of a TV program that aired on ITV in England on 8 November. Four celebrities took DNA tests to identify their vulnerability to genetics-based disease. DNA tests are a better approach to assessing genetic susceptibility more often addressed when the family doctor asks about family history of certain diseases.

The program turned out to be a bit of an advertorial for the UK company Genetic Health. Some time was spent on "why take a test." Because for many diseases genetics is only one risk factor knowing about "bad genes" can spur you on to lifestyle changes. In some instances these can entirely compensate for an adverse genetic risk. They argue that if you have a regular medical checkup then a DNA test is a logical extension of the precaution.

The argument fails where a DNA test can identify a genetic risk for which nothing can be done, and the program showed one celebrity struggling with whether to take a test for vulnerability to Alzheimer's for which there was a recent family history and no treatment. She ended up declining the test.

By contrast one of the subjects had been concerned about a family history of heart disease, and was delighted to learn that his risk was low. The program quoted the statistic that 90% of people offered a test choose to take it. In presenting test results showing elevated risk the doctor was careful to quickly follow on with suggestions for compensatory lifestyle changes.

There were a few areas where the program could have been better. In making the decision about whether to take a test there was no discussion of the possible impact on ability to get life or health insurance, nor the possible impact on others. As someone with a science background I would have liked to have seen some discussion of the error bands on the assigned genetic risk.

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