Mihaescu, R., van Hoek, M., Sijbrands, E., Uitterlinden, A., Witteman, J., Hofman, A., van Duijn, C., & Janssens, A. (2009). Evaluation of risk prediction updates from commercial genome-wide scans Genetics in Medicine, 11 (8), 588-594 DOI: 10.1097/GIM.0b013e3181b13a4f
Caroline Wright from the Public Health Genomics Foundation
has a concise post
describing the results from a recent paper in Genetic Medicine
. The paper evaluates the probability that personal genomics customers will find that their predicted risk of a common disease changes significantly over time as their genetic data are updated, using data on known type 2 diabetes risk variants as a case study.
As you might expect, when hypothetical customers started with information from only one risk variant and then had information from other risk variants and from non-genetic predictors (age, sex, body mass index) added in, their predicted risk often changed from above- to below-average and vice versa
. A similar result was predicted by Peter Kraft and David Hunter in a New England Journal of Medicine perspective piece
they wrote back in April.
You can spin this as a negative – by arguing that such shifting risk predictions will confuse customers and undermine the public’s view of the reliability of genetic risk prediction – but really such a result is a logical consequence of slow improvements to any new and imperfect risk prediction system.
Personal genomics customers should of course treat their current risk predictions with caution – for most diseases, current risk predictions are barely better than noise – and bear in mind that their profiles will alter over the next few years as increases in scientific understanding of the genetic basis of disease improves, and as their predictions become steadily more accurate.
Wright provides a balanced review of the implications of the article, and finishes with a paragraph worth quoting verbatim:
However, far from supporting calls to forbid such tests being available DTC, this highlights the need for transparency in the provision of information.Companies offering genome-wide risk prediction services should ensure that their customers understand that, whilst the measurement of the DNA sequenceitself (the assay) will remain constant, the interpretation of the result (the test) is likely to change as the science develops.
Amen. As I have consistently argued here on Genetic Future, the solution to the alleged dangers of personal genomics is not banning the public from having access to their own genome (as Germany has recently done
), or forcing them to seek permission from their doctor before peering into their own DNA. Instead, the answer is to ensure that companies provide at least the minimal information required for customers to make an informed decision about the utility of risk predictions
, and to punish those companies who fail to do so with public censure and (if absolutely necessary) regulatory action.