Direct-to-Consumer Genetic Testing Summary of a Workshop (2011) / Chapter Skim
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Scientific Foundations for Direct-to-Consumer Genetic Testing
Scientific Foundations for Direct-to-Consumer Genetic Testing
Pages 7-12
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From page 7... ...
1 Unless otherwise noted, the section "Genomic Associations" reflects the remarks of Alan Guttmacher, former director of the National Human Genome Research Institute, National Institutes of Health. 2 Glazier A, Nadeau J, Aitman T., Finding genes that underlie complex traits, Science, 2002: 298 (5602)
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From page 8... ...
At this price, it is conceivable that whole genome sequencing will eventually replace genome wide association studies. Although a GWAS can be a powerful source of information about genetic predisposition to disease, so far these studies explain only a very small fraction of heritability and fail to capture other contributing factors such as multiple common genetic variants acting together, copy number variants, or epigenetics -- chemical changes in base pairs, or physical changes in chromosome structure -- that may greatly modulate phenotypic expression but that are themselves typically not heritable.
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From page 9... ...
. A recent exception came to light just prior to the workshop: a software glitch had caused one DTC genetic testing company to confuse human and animal mitochondrial DNA.4 Assessing other factors in clinical validity, however -- particularly a test's value in predicting disease and calculating risk -- presents more complex challenges, many of them in the context of GWAS SNPs: • Credible genetic associations: Whether or not a clear association has been established between a particular SNP and an increased likeli hood of developing a specific disease.
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From page 10... ...
Looking at heart disease, for example, it takes an estimated 20 or more SNPs to get a two-fold increased risk, whereas family history has much greater predictive value; it could be therefore, that awareness of SNPs contributes little or no additional value. In at least two cases, however -- coronary heart disease (nine SNPs)
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From page 11... ...
One long-lasting and far-reaching benefit of the Human Genome Project to scientific research -- and one that is often overlooked in favor of headline-grabbing advances in genomics -- is the landmark agreement among participating centers to post their sequencing data every 24 hours. As beneficial as this advance has been in many ways, it has highlighted the need to balance three imperatives: enabling rapid public access to all data generated from publicly funded research; encouraging research by offering researchers exclusive use of their data for a period of time; and protecting participants' rights, including pri vacy.
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From page 12... ...
• With the cost of locating all the SNPs associated with genetic contributions to any complex disorder rapidly becoming affordable, what process and criteria will be used to decide which common diseases will be explored and in what order? • If DTC genetic testing companies are capable of confusing human and animal DNA, should they be providing genetic testing services to customers at all?
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