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Promises and perils of using genetic tests to predict risk of disease

BMJ 2020; 368 doi: (Published 07 February 2020) Cite this as: BMJ 2020;368:m14

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Direct-to-consumer genetic testing

  1. Ian A Scott, director of internal medicine and clinical epidemiology and professor of medicine12,
  2. John Attia, professor of medicine and clinical epidemiology and consultant34,
  3. Ray Moynihan, assistant professor and honorary associate professor56
  1. 1Princess Alexandra Hospital, Woolloongabba, QLD, Australia
  2. 2University of Queensland, Brisbane, QLD, Australia
  3. 3University of Newcastle, Callaghan, NSW, Australia
  4. 4John Hunter Hospital, Newcastle, NSW, Australia
  5. 5Institute for Evidence-Based Healthcare, Bond University, Robina, QLD, Australia
  6. 6Sydney Medical School—Public Health, University of Sydney, Sydney, NSW, Australia
  1. Correspondence to: I A Scott ian.scott{at}

In determining risk of future disease, Ian Scott and colleagues argue there is little value in genetic testing of asymptomatic people with no family history of disease

Key messages

  • Low cost genetic testing is increasingly being used by patients and the public to predict risk of developing disease in asymptomatic people in the hope that more precise risk stratification might facilitate targeted interventions for reducing risk

  • The proliferation of genetic variants might cause clinicians and citizens to misread their clinical relevance, potentially leading to overestimation of risk, overdiagnosis, and overtreatment

  • In appraising the value of genetic testing for clinical decision making, consideration must be given to validity, predictive accuracy, clinical utility, potential harms, cost effectiveness, and feasibility of use in routine care

  • Moving from traditional genetic testing for rare monogenic disorders within families to wider polygenic testing for common diseases in heterogeneous populations requires robust evidence of benefits and harms of this paradigm shift

Increasing numbers of patients and clinicians are undertaking low cost genetic testing in asymptomatic people to identify genetic variants that might predict risk of developing diseases. By early 2018, an estimated one in 25 citizens of the United States had undergone genetic testing, more than double the rate in the previous year.1 Although testing for risk of monogenic diseases such as cystic fibrosis in people with family histories is often appropriate, extending testing for polygenic diseases such as cardiovascular atherosclerosis to people with no family history is problematic and might cause harm.

Tests for approximately 75 000 genetic variants are now commercially available from companies such as 23andMe, Navigenics, and deCODE Genetics, which can be ordered on the internet by consumers anywhere in the world and are increasingly advertised in lay media in the US, Canada, Australia, and various European countries.2 These tests aim to predict individual …

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