The era of healthcare that may emerge from this type of testing has been coined “preventative healthcare” – in other words, if one knew what diseases he was predisposed to, i.e. cardiovascular disease, he may think twice about gulping down that bacon triple cheeseburger, extra large fries, and apple pie – and may even pass on the after dinner smoke (God forbid). That said, he may even take up running and consume a diet low in fat and cholesterol.
DTC genetics drastically differs from the current paradigm in genetic testing. Traditionally genetic tests are typically considered (by a physician, provided patient consent is obtained) if a person has a family history of a disease, shows symptoms of a genetic disorder, or is concerned about passing on a genetic problem to their children. Any genetic test, however, can open up ethical and/or psychological problems and thus a patient is often encouraged to discuss results with a genetic counselor, medical geneticist, or primary care doctor who can help them understand and cope with the results, or adjust their lifestyles accordingly.
In contrast DTC genetics involves an individual obtaining a genetic test without having to go through a healthcare professional. This process differs from the traditional route, whereby a patient sees their primary care doctor and the physician orders the genetic test. In the case of consumer genetics, the individual orders the test himself, usually over the web, and pays for it. The person also receives the results directly and decides what to do with them – in some cases the option to speak with a genetic counselor is not provided.
DTC genetics interrogate multiple categories of disease predisposition, ranging from monogenic diseases (diseases caused by a single gene), i.e. cystic fibrosis, sickle cell anemia, or Huntington’s disease - there are 6,000 known single-gene disorders - to those that are multigenic (caused by multiple genes). OK, so we just brought up monogenic and multigenic disease states. Is one type easier to test for than the other? The answer is “Yes”
Just How Accurate are the Results Tests Based on DTC Genetics
The current DTC genetic tests are based on interrogating markers within DNA. For monogenic diseases, it is easier to determine whether a predisposition exists as the causative gene, and the mutations (used as biomarkers) within the gene have been pinpointed.
By contrast, the causative genes for the majority of multigenic diseases have not been identified, nor are the biomarkers that can be used for diagnostic purposes, agreed upon by the scientific and medical community. To add to the confusion, some companies have secured the rights to particular biomarkers and can prevent others from using them. In other words – a DTC genetic test from company X that tests for predisposition to cardiovascular disease, may not use the same biomarkers to test for cardiovascular disease as company Y.
Who has the more accurate biomarkers? Therein, lies the debate – which are more predictive, and for for that matter, which have no predictive value whatsoever?
What are the Current Offerings?
A person may be more interested in having a screening for a variety of possible diseases. These tests use DNA analysis and web-based tools to provide insight into a person’s ancestry, genealogy and propensities to many traits and diseases. Companies like 23andMe (www.23andme.com) do a genetic scan that includes genetic analysis on many diseases, traits, and conditions. Navigenics (www.navigenics.com) uses the latest science and technology to give a person a view into their DNA, revealing their genetic predisposition for important health conditions and empowering the person with knowledge to help them take control of your health future. Knome (www.knome.com), which was the first personal genomics company to offer complete genome sequencing, produces a complete and comprehensive analysis of trait and disease associations available on the market today.
These companies provide information on your ancestry – which parts of the world did your forbears come from. They also give you information about your predilection to disease based on your individual genetics. A company like Knome, which provides a gull genome scan, looks at your entire genome; most firms, such as Navigenics, 23andMe, and deCodeMe provide selected information on a subset of the genome. Because of these differences, prices range from roughly $400 to $100,000 for an analysis.
Why might it be useful to have an analysis done?
A person with a family history and first-degree relatives who have had a genetically-based disease may want to have a test done to see if he or she carries the gene. Some people want to know; others don’t – it’s an individual decision. One may be curious about where her ancestors came from. Also, it’s interesting to have a genetic scan done in order to see what recessives one carries – recessives are genes that need to come from both parents in order to show up in offspring. Blue eyes are an example of a recessive. But a gene scan may provide more important information about a recessive which is related to a serious problem. Also, if one hears of an increased risk of heart disease or diabetes, for example, it’s possible to make lifestyle changes to minimize the potential problem.
Why might it be useful to go to a consumer genetics company for a test?
More and more, patients are turning into consumers and taking charge of their own health care. And despite the passage in 2008 of GINA legislation (The Genetic Information Nondiscrimination Act of 2008) which is designed to prohibit discrimination in insurance and employment, individuals still worry that disclosing negative genetic information to employers, or having it appear in a medical record may create problems. Going to a private commercial source gives the buyer the opportunity to make a decision about whether or not to share the information with a primary care physician.
Of course, knowing the information about one’s genetic make-up raises ethical and social issues. What does the information mean? What are the probabilities for disease associated with carrying the gene? How should a person to deal with the information in his own life? What should be told to family members? How does one find out which family members want to know? These are a few of the important issues around dealing with the results of genetic testing. Responsible consumer genetics firms make available genetic counseling from trained professionals as part of their offerings.
The technology for this kind of testing is rapidly improving and prices are coming down. The majority of these tests are performed using SNPs as biomarkers. A SNP (single nucleotide polymorphism) is a one base difference between an individual’s genome and the ”reference genome”. In other words – there are 30 Billion letters (or bases) in the genome – between you and me, there is a one base difference roughly every
3,000 letters. These differences are what makes us unique.
The technology used to interrogate 1MM SNPs costs ~$300/sample, still a somewhat high price for the average consumer, although new methodologies are promising to bring this price down to under $50 within the next year. This will make these tests much more affordable to the average consumer.
With personal genetics and direct-to-consumer (DTC) genetic tests becoming more available, leading stakeholders from across the country will be convening together for the first time in Boston from June 9-11 at the Consumer Genetics Conference [http://www.consumergeneticsshow.com] to examine all the aspects and perspectives of this emerging field, and the challenges, issues and opportunities it will bring. This conference is open to everyone including companies involved in the space, scientists, medical doctors, genetic counselors and even consumers.
Delphi Bio, LLC
Organizer, Consumer Genetics Conference
COO, Genomic Healthcare Strategies
Organizer, Consumer Genetics Conference
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