Direct-to-Consumer Genetic Testing: Reliable or Risky?

Washington University/Barnes-Jewish Hospital, St. Louis, MO, USA.
Clinical Chemistry (Impact Factor: 7.77). 09/2011; 57(12):1641-4. DOI: 10.1373/clinchem.2011.167197
Source: PubMed
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    ABSTRACT: It is the position of the Academy of Nutrition and Dietetics that nutritional genomics provides insight into how diet and genotype interactions affect phenotype. The practical application of nutritional genomics for complex chronic disease is an emerging science and the use of nutrigenetic testing to provide dietary advice is not ready for routine dietetics practice. Registered dietitian nutritionists need basic competency in genetics as a foundation for understanding nutritional genomics; proficiency requires advanced knowledge and skills. Unlike single-gene defects in which a mutation in a single gene results in a specific disorder, most chronic diseases, such as cardiovascular disease, diabetes, and cancer are multigenetic and multifactorial and therefore genetic mutations are only partially predictive of disease risk. Family history, biochemical parameters, and the presence of risk factors in individuals are relevant tools for personalizing dietary interventions. Direct-to-consumer genetic testing is not closely regulated in the United States and may not be accompanied by access to health care practitioners. Applying nutritional genomics in clinical practice through the use of genetic testing requires that registered dietitian nutritionists understand, interpret, and communicate complex test results in which the actual risk of developing a disease may not be known. The practical application of nutritional genomics in dietetics practice will require an evidence-based approach to validate that personalized recommendations result in health benefits to individuals and do not cause harm.
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    ABSTRACT: Technological advances have greatly increased the availability of human genomic sequencing. However, the capacity to analyze genomic data in a clinically meaningful way lags behind the ability to generate such data. To help address this obstacle, we reviewed all conditions with genetic causes and constructed the Clinical Genomic Database (CGD) (, a searchable, freely Web-accessible database of conditions based on the clinical utility of genetic diagnosis and the availability of specific medical interventions. The CGD currently includes a total of 2,616 genes organized clinically by affected organ systems and interventions (including preventive measures, disease surveillance, and medical or surgical interventions) that could be reasonably warranted by the identification of pathogenic mutations. To aid independent analysis and optimize new data incorporation, the CGD also includes all genetic conditions for which genetic knowledge may affect the selection of supportive care, informed medical decision-making, prognostic considerations, reproductive decisions, and allow avoidance of unnecessary testing, but for which specific interventions are not otherwise currently available. For each entry, the CGD includes the gene symbol, conditions, allelic conditions, clinical categorization (for both manifestations and interventions), mode of inheritance, affected age group, description of interventions/rationale, links to other complementary databases, including databases of variants and presumed pathogenic mutations, and links to PubMed references (>20,000). The CGD will be regularly maintained and updated to keep pace with scientific discovery. Further content-based expert opinions are actively solicited. Eventually, the CGD may assist the rapid curation of individual genomes as part of active medical care.
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    ABSTRACT: BACKGROUND: The advent of direct-to-consumer (DTC) genetic testing (GT) has sparked a number of debates regarding the scientific validity of tests, their broad health and ethical implications for society as well as their legal status. To date, relatively few empirical studies have been published regarding this phenomenon. We conducted a survey of European clinical geneticists to gauge their awareness of, experiences with, and attitudes towards DTC GT. METHODS: We invited 300 clinical geneticists from 28 European countries to complete an online questionnaire. Statistical analyses of closed-ended questions were performed using the STATISTICA software package. Answers to open-ended questions were analyzed for recurring themes. RESULTS: 131 clinical geneticists answered our survey (response rate= 44%). 86% (110/128) of respondents were aware of DTC GT, and over one-third had been contacted by at least one patient regarding these services. The majority (84%) of respondents did not agree with telephone medical supervision outside of an established doctor-patient relationship. The majority of clinical geneticists also found it unacceptable to provide non-face-to-face medical supervision for: i) a presymptomatic test for a condition with very high penetrance; ii) a predictive test for a condition that has a 'medium' penetrance of 50 to 60%; and for iii) carrier testing. For conditions that are neither treatable nor preventable and for disorders with serious health consequences, clinical geneticists were almost unanimous in expressing the unacceptability of offering such genetic tests outside of the traditional health care setting, without an established physician-patient relationship and without face-to-face medical supervision. CONCLUSION: A high percentage of European clinical geneticists are aware of DTC GT and the majority do not agree with the model of provision used by many commercial companies for certain severe or actionable health conditions. Despite this disagreement with the DTC model of provision, over 85% of respondents said that they would offer genetic counselling to patients who asked for a consultation after having undergone DTC genetic testing. The understanding of the views and opinions of this expert stakeholder group should be considered in attempts to shape responsible policy and guidelines for these services.
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