# Direct-to-Consumer Genomics: Harmful or Empowering? A Patient's Guide to Home DNA Testing

The price of whole-genome sequencing has dropped 100,000-fold in 15 years, making personal DNA analysis affordable for the average American consumer and sparking a boom in direct-to-consumer (DTC) genomics testing. This article examines whether bypassing doctors and genetic counselors to get personal genetic risk information is harmful or empowering. Studies show that while genetic risk disclosure rarely causes lasting psychological harm, it also does little to motivate healthier behavior, and for most complex diseases, the clinical validity of gene-based predictions remains weak. Experts argue that people should have unfettered access to their own genomic data, but that physician and genetic counselor involvement still plays a critical role in interpreting results and guiding healthcare decisions.

# Direct-to-Consumer Genomics: Harmful or Empowering? A Patient's Guide to Home DNA Testing

## Table of Contents

- Key Points
- Introduction: The Genomics Revolution Comes Home
- Genetic Disease and Genetic Risk: What Your Genes Really Tell You
- The Direct-to-Consumer Genomics Business Model: How It Works
- Disintermediating Access to Medical Data: Cutting Out the Doctor
- The Access Debate: Should You Have Unrestricted Access to Your Own Genome?
- Data Interpretation: What Your Results Actually Mean
- The Future of Personalized Genomics and the Doctor-Patient Relationship
- Clinical Implications for Patients
- Limitations of This Research
- Recommendations for Patients
- Frequently Asked Questions
- Source Information

## Key Points

- Genetic risk is not destiny; even for APOL1, only 20% of people with two risk copies develop kidney disease.
- Most gene-disease associations have weak clinical validity; predictions for complex diseases are often problematic.
- Studies show genetic risk disclosure causes only transient distress but does little to motivate healthier behavior.
- Every healthy person carries about 100 loss-of-function mutations, so finding variants is normal.
- Different DTC companies can give different risk predictions; online symptom checkers are accurate only 43% of the time.

## Introduction: The Genomics Revolution Comes Home

The sequencing of the human genome is transforming medicine in ways that directly affect patients. In just a few years, the underlying molecular basis for thousands of genetic disorders will be known. But perhaps the most dramatic change is economic: the price of whole-genome sequencing has fallen within the budget of the average American consumer.

One of the key dividends of the Human Genome Project was driving down the cost of DNA sequencing by five orders of magnitude—a 100,000-fold reduction—in just 15 years. To put that in perspective, Moore's law (as modified by David House) describes computer speed as doubling in performance every 18 months. From 2001 to 2007, the decrease in genome sequencing cost followed Moore's law. But after 2008, the drop in DNA sequencing cost sank far faster than Moore's law would predict.

Recent revolutions in DNA sequencing technology, combined with rapid advances in computational speed and data storage, have reduced the cost of genome sequencing and analysis to a level that makes it practical for middle-class Americans to obtain their genome sequence in just a few days. For a few hundred dollars, anyone can now get their DNA analyzed for a variety of personal traits and disease risk factors.

This raises three critical questions for patients and their doctors:

- What effect will this information have on patient care?
- How much do we currently know about the predictive power and clinical validity of DNA sequence-disease associations?
- How should the clinical care community respond to this information revolution?

## Genetic Disease and Genetic Risk: What Your Genes Really Tell You

The language used in the popular press to describe inherited disease is confusing, and it often misleads patients. People routinely speak of the "gene for sickle cell disease" or the "gene for hemophilia." But there is no single gene for sickle cell disease. The gene altered in sickle cell anemia is the adult beta globin gene, and everyone has two copies of it.

What distinguishes patients with sickle cell disease is that they carry a particular variant—a so-called "allele"—of the adult beta globin gene. This variant makes red blood cells clump abnormally in the capillaries under low oxygen tension, resulting in transient painful crises and long-term organ damage.

It is also important to understand that all mutations are not alike. Sickle cell disease occurs in people with two copies of the same adult beta globin gene allele, both of which program an abnormal protein. Other alleles of the adult beta globin gene result in little or none of the beta globin protein—a condition called beta thalassemia. The severity of beta thalassemia can vary, depending on the nature of the allele and whether one or both copies are altered, but its clinical presentation is distinct from sickle cell disease.

Personal genomics testing can certainly determine whether a patient carries a mutant adult beta globin gene, and the clinical data concerning this gene are sufficient to provide useful interpretations of the results.

If the public discourse surrounding simple inherited (Mendelian) diseases is sometimes misleading, the idea of disease risk for complex diseases is infinitely more challenging. For common medical conditions like age-related macular degeneration, asthma, depression, heart disease, hypertension, obesity, and type 2 diabetes, there are multiple genetic factors with various contributions, as well as environmental inputs.

In some cases, gene sequence variants are statistically more often encountered in affected individuals. Yet others may have the same variants without any symptoms. An illustration of this is the association of the APOL1 allele with chronic kidney disease (CKD). While CKD was thought to be a complex disease, the presence of the APOL1 allele can account for much of the risk. But only approximately 20% of individuals who carry two copies of the APOL1 allele actually develop CKD—unless they also suffer from another condition such as HIV infection. For most people with APOL1-related CKD, the influence of such secondary factors is unknown, making it hard to predict who will get CKD.

This leads to a critical takeaway for patients: **genetic risk is not the same as genetic destiny**. The utility of genomics data depends on the predictive power associated with specific alleles at specific genes, and on appreciating the clinical validity behind any given prediction. In most cases of sequence variants uncovered by personal genomics testing, the clinical validity of allele associations with complex diseases is weak or nonexistent, making the predictive power of such testing problematic at best.

## The Direct-to-Consumer Genomics Business Model: How It Works

A variety of genomics testing services are presently marketed directly to consumers without a doctor's order. Some companies test for a handful of specific genes, looking for alleles with clinically informative data or significance for ancestry. Other companies sequence the "exome"—that fraction of the genome that contains genes encoding proteins. This represents only about 1% of the human genome, making the amount of data and the task of assembling and validating it much more manageable than sequencing the entire genome.

The remainder of the genome encodes:

- Sequences that control protein-coding genes
- Non-coding RNAs that regulate protein-coding genes
- Transposable elements (so-called "jumping genes")
- Sequences that control chromosome behavior
- Sequences with no known function

However, with the rapidly declining cost of DNA sequencing and growing computational speed and data storage capacity, many companies now offer whole-genome sequencing as well.

As of June 2016, the following companies were offering direct-to-consumer DNA testing in the United States:

-
**23andMe** — ancestry and ethnicity, traits, genetic disease carrier status, wellness
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**AncestryDNA** — ancestry and ethnicity
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**Counsyl** — inherited cancer gene screening, pre-natal and pre-conceptional screening
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**DNA4Life** — drug sensitivity report, wellness review, skin care report
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**DNA-CardioCheck, Inc.** — clotting and cardiovascular disorders
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**FullGenomes** — deep ancestry
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**Gene by Gene** — research, exome sequencing, whole-genome sequencing
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**Genographic Project** — deep ancestry
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**Genomic Express** — ancestry, nutrition, pharmacogenetics, sports, traits
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**Genos** — exome sequencing for disease risk, athletic or nutritional predispositions (does not accept orders from NY or FL)
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**Healthspek PGT** — pharmacogenetics (how your genes affect your response to drugs)
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**Interleukin Genetics** — periodontal disease, weight management, heart health, bone health, nutritional needs
-
**InVitae** — cardiology, hematology, hereditary cancer, metabolic diseases, newborn screening, neurology, ophthalmology, pediatric genetics
-
**Kailos Genetics** — cancer screening, pharmacogenetics, ADHD
-
**Sure Genomics** — health, whole-genome sequencing
-
**Ubiome** — gut microbiome sequencing
-
**Veritas Genetics** — whole-genome sequencing, BRCA, prenatal testing (requires a doctor's order)

Obtaining a highly accurate entire genome sequence of a single person is relatively easy compared with making sense of that information. The raw sequence information is fragmentary; hundreds of millions of fragments must be assembled by computer into the linear sequences comprising the three billion nucleotide units in a human genome. Then, there is the reality that the chemistry of DNA sequencing isn't flawless, so sequencing errors have to be distinguished from actual variants. Finally, there is the question of whether the validated variants are simply random and benign, or have meaning for a person's ancestry or health.

Probably the most widely advertised consumer genomics provider is 23andMe, a privately held online biotechnology company based in Mountain View, California. The company sends customers a container in which they deposit a saliva sample. Once returned, the company extracts and genotypes the DNA, then sends the customer a research report showing whether they are a carrier for any of more than 35 diseases, plus information about benign traits and likely ancestry.

Patients should understand the business model behind these services: 23andMe collects genetic data in order to identify patterns and aggregate information to sell to researchers, insurers, and pharmaceutical companies. Anticipating the future market value of this database to commercial partners, 23andMe steeply subsidizes the cost of its services to individual consumers.

In all but one case, the companies listed above work directly with consumers without a doctor's order.

## Disintermediating Access to Medical Data: Cutting Out the Doctor

"Disintermediation" is the process of bringing customers closer to products or services by cutting out intermediaries. A familiar example is the farmer's market, where farmers sell produce directly to consumers without the intermediation of a grocery store. More recent examples include the Uber app, which connects people directly with a car and driver without the intermediation of a taxi company, and Airbnb, which gives travelers access to overnight accommodations without the intermediation of hotel companies.

Consumer genomics disintermediates personal genetic information by removing the physician and genetic counselor from the process. The expertise required of physicians is orders of magnitude more complex than that required for farming, driving a car, or renting a room, so the idea of removing the doctor from the collection and interpretation of personal medical data would seem to threaten the traditional medical information hierarchy.

In reality, disintermediation has been occurring in medicine for decades. Digital thermometers, blood pressure cuffs, blood sugar monitors, and pregnancy testing kits are examples of commercialized technologies that permit the lay public direct access to actionable health-related parameters without overt symptoms or physician intermediation.

The public is increasingly using online "symptom checkers" to seek diagnoses and advice on appropriate care. In a recent study, 23 such online applications were evaluated for accuracy in a total of 770 standardized patient evaluations for diagnosis and 532 standardized patient evaluations for triage (deciding how urgently care is needed). The results were sobering:

- The correct diagnosis was listed first in only **43%** of standardized patient evaluations overall
- The correct diagnosis was listed in the top 20 diagnoses only **58%** of the time
- Appropriate triage advice was given in only **57%** of cases
- By comparison, in-person physician diagnostic accuracy rates are **85–90%**

With regard to online diagnostics, the message for patients is *caveat emptor*—let the buyer beware.

Direct-to-consumer marketing of genomics data may also be compared to the widely accepted direct marketing of MRI and CT imaging of the coronary arteries for calcification, and of the breasts, lungs, and abdominal organs for cancer. But there is a critical difference: CT imaging involves ionizing radiation exposure, a known cancer risk. Radiation exposure during a full-body CT scan is approximately **500 times** that of a chest X-ray.

While a small number of individuals could discover tumors this way, only a fraction of these people will have an altered outcome. On the other hand, benign lesions uncovered incidentally during imaging—so-called "incidentalomas"—can lead to needless invasive testing and anxiety. For screening the "worried well," the risks of asymptomatic CT imaging clearly outweigh the benefits. While MRIs lack the ionizing radiation risks, the possibility of actionable false positives remains.

The critical health care issues that emerge from direct-to-consumer marketing of genomic data are:

1. Should consumer access to personal genomics data be denied or controlled?
1. What can and cannot be claimed concerning the medical implications of the data?

On the first issue, the author argues that people should have **unfettered, disintermediated access to their personal genome data**. On the second, there are legitimate controls that should be imposed on the marketing of claims about personal genomic data.

## The Access Debate: Should You Have Unrestricted Access to Your Own Genome?

In an open society, maximizing autonomy is a virtue. Knowledge is power. The concerns expressed around disintermediated access to personal genomics data focus on whether such data could cause significant harm to the individual. There is certainly anecdotal evidence of severe emotional distress associated with disintermediated genetic testing that resulted in unexpected risk findings. Fortunately, several recent studies have been published that address these concerns directly.

### Does genetic risk information about the ApoE4 allele increase distress and anxiety?

The ApoE4 allele is associated with Alzheimer's disease. The presence of one copy of the ApoE4 allele increases the risk of Alzheimer's by approximately **three-fold**, while two copies increase risk approximately **fifteen-fold**.

In a study of **162 asymptomatic adults** who had a parent with Alzheimer's disease, each subject's symptoms of anxiety, depression, and stress were measured after test results were revealed. Genetic counselors monitored all subjects for adverse psychological effects and made referrals when appropriate. The study found evidence that disclosure of genotyping information provides a benefit to those who are ApoE4-negative and results in only transient, modest distress to ApoE4-positive individuals.

A caveat here is that there is no proven medical intervention for Alzheimer's disease. In the case of bilateral prophylactic mastectomy (surgical removal of both breasts) in response to increased genetic risk for breast cancer, it is possible that anxiety and distress may be quite different when contemplating invasive therapy.

### Do elevated cancer risk results alter risk perception?

In surveys of over **1,000 people** examining the effect of risk information for four common cancers, a study found that DTC genomic testing results indicating elevated risk did lead to increased risk perception, while an average risk result left risk perception unchanged or lower.

### Do genetic risk data motivate risk-reducing behavior?

Based on a review of **14 papers** reporting results of seven clinical studies and six analogue studies, Marteau and colleagues reported that **"communicating DNA-based disease risk estimates has little or no effect on smoking and physical activity."** The same could well be said of the common long-term patient response to standard DNA-free doctor's admonitions concerning weight loss, smoking cessation, alcohol moderation, sunscreen use, and regular exercise.

Taken together, the current published literature suggests **no lasting harm comes from giving people access to their genomics data, although little benefit could be quantified either**.

On the issue of DTC genomics testing, there is no justification for medical paternalism, defined as "usurpation of decision-making power, by preventing people from doing what they have decided, interfering in how they arrive at their decisions, or attempting to substitute one's judgment for theirs, expressly for the purpose of promoting their welfare." Thus, disintermediated access to personal genomics data is **not contraindicated**.

The table below summarizes the potential advantages and disadvantages of predictive genetic testing:

**Potential Advantages:**

- More information
- Allows early intervention
- Allows more personal control for the individual
- Possibility of saving public healthcare resources if testing and treatment are conducted privately
- Can alert relatives to important genetic conditions

**Potential Disadvantages:**

- Costs to individuals of tests that yield little determinate information
- Social harms when private testing can undermine equal access to healthcare
- Costs of consequences of having information when it is inaccurate or hard to interpret
- Costs when nothing can be done about the condition identified
- Inaccurate risk assessments leading to false reassurance or misplaced anxiety
- Results leading to stigma or other effects that may be regretted, given that information once known cannot be "un-known" (for example, in insurance declarations)
- Costs to taxpayers when unnecessary follow-up testing and treatment is carried out
- Costs and harms to third parties when children or other family members are tested without consent, or when embryos are tested for conditions whose risks may be hard to determine

## Data Interpretation: What Your Results Actually Mean

The second major concern for direct-to-consumer genomics testing is that the current state of medical knowledge has not kept up with the detail with which we can examine genomes. So what should DTC genomics testing companies be allowed to tell their clients about the meaning of sequence variation?

Many or most genomic testing clients are interested in whether they carry a mutation that affects their health or the health of their descendants. An obvious place to look for such mutations is in genes that code for proteins, and whether there is a mutation that would inactivate one or both copies of that gene.

A 2012 paper reported an exhaustive analysis of **185 human genomes** of healthy people, looking specifically for changes that would result in complete loss of function in any of their protein-coding genes. The analysis found that the typical "healthy" person has about **100 such mutations** in their genome, with about **20 of these changing both copies of the gene**.

Most of the loss-of-function variants found in specific individuals appear to be common variants that occur in non-essential genes, and there is little or no evidence implicating these loss-of-function mutations in common complex diseases like heart disease or type 2 diabetes. Some loss-of-function variants are rare, suggesting that they are deleterious, and some of these could be associated with serious disease conditions.

However, our current ability to predict risk from genomics data is weak or nonexistent for most sequence variants. Simply knowing that there are sequence variants that disrupt a specific gene is not enough reason to seek medical intervention. Indeed, a recent study comparing the ability of three DTC genomics companies to assess risk for six common complex diseases—age-related macular degeneration, atrial fibrillation, celiac disease, Crohn's disease, prostate cancer, and type 2 diabetes—using data sets simulating **100,000 individuals** found that the companies' genomic data analysis varied significantly in their predictive ability for each disease and in the risks predicted for individual consumers.

For now, stringent standards are essential for published disclaimers concerning the limitations of current knowledge of risks attached to most sequence variants in light of current scientific evidence. Of course, the standards must be evolvable as the evidence inevitably improves with time.

Even with better data on gene function, low health literacy and low genetic literacy are barriers to the ability of consumers to use personal genomic data as a guide to health care decision-making. Both barriers necessarily affect perception of risk, which is also influenced by education, ethnicity, and culture. Here lies a critical role for intermediation, either by a genetically literate physician or a genetic counselor.

Of course, clinically significant responses to genomic data will still require standard medical protocol; patients who seek a mastectomy or ovariectomy based on genomics data will still face physician intermediation in this country.

With the widespread availability of disintermediated genomics data, are we really better informed about our health? What happens when a consumer of genomics data learns they carry a mutation associated with elevated risk for colon or breast cancer? Or more dramatically, consider a 25-year-old who learns they carry a mutation giving the certainty of dying of Huntington disease in their fourth or fifth decade of life, when no mitigating therapies exist.

While psychological evaluation and genetic counseling are standards advocated by the medical community prior to specific testing for Huntington disease, disintermediated testing provides no such mechanism to prepare consumers of commercial testing for bad news and the risk of anxiety, emotional distress, depression, and suicidal ideation.

Studies conducted in collaboration with 23andMe so far have shown no evidence of adverse effects. However, current users of 23andMe skew toward an emotionally, intellectually, and educationally prepared demographic with sufficient affluence and access to health care to cope with adverse news.

Nevertheless, the terms of service on the 23andMe web site stipulate that "information you learn from 23andMe is not designed to independently diagnose, prevent, or treat any condition or disease or to ascertain the state of your health in the absence of medical and clinical information," and "23andMe makes no warranty that the results that may be obtained from the use of the services will be accurate or reliable."

Regardless, it is clear that more and more personal medical data will be finding their way unfiltered directly to consumers. This represents a significant shift in control from doctors to the general public. In the absence of physician oversight, will this new access result in a significant impact on outcomes?

In the cases of diabetes and heart disease, most people don't need test data or a doctor to know that a better diet and regular exercise will improve their health. Will whole-genome data change patient behavior for the better? So far, it looks like the risk data currently available from direct-to-consumer personal genomics are **neither as empowering as claimed by the companies promoting this product, nor as dangerous as critics have feared**.

## The Future of Personalized Genomics and the Doctor-Patient Relationship

At its best, direct-to-consumer genomics testing could eventually become like other forms of home medical testing—another way for people to take personal control of their health and wellness. According to a recent study, the reliability of current genomic sequencing technology surpasses the accuracy of Sanger DNA sequencing, long held to be the gold standard.

Today, however, genomics testing to assess risk for complex diseases rests on a weak foundation of clinical validation. Thus, in most cases, genomics data cannot serve as a guide to action.

While medical paternalism is not warranted in controlling access to personal genomics data, there may be a benefit for some genomics testing clients to access pre-test intermediation by physicians or genetic counselors to prepare for adverse news. There is also a need for a stronger post-hoc (after-the-fact) role for physician intermediation in interpreting risk, prescribing risk-reducing interventions, and managing the clinical consequences of genomic findings.

## Clinical Implications for Patients

For patients considering or already using direct-to-consumer genomics testing, several important clinical implications emerge from this review:

-
**Genetic risk is not destiny.** Even for well-studied genes like APOL1, only about 20% of people with two risk copies develop the disease, and additional factors play a major role.
-
**Most gene-disease associations have weak clinical validity.** For complex diseases like heart disease, diabetes, and depression, the predictive power of most sequence variants is problematic at best.
-
**Testing results rarely cause lasting psychological harm.** Studies of ApoE4 and cancer risk disclosure found at most transient distress, with some benefit to those who receive negative results.
-
**But testing rarely changes behavior either.** A review of 14 studies found that DNA-based risk estimates have little or no effect on smoking and physical activity.
-
**Every healthy person carries about 100 loss-of-function mutations.** Finding variants in your genome is normal and does not mean you are sick or will become sick.
-
**Different companies can give different risk predictions.** A study comparing three DTC companies found significant variation in predictive ability and risk estimates for the same diseases.
-
**Your data may be sold.** Companies like 23andMe aggregate and sell genetic data to researchers, insurers, and pharmaceutical companies, subsidizing the low cost to consumers.
-
**Online symptom checkers and direct-to-consumer tests cannot replace professional judgment.** Online diagnostic tools were accurate only 43% of the time compared with physicians' 85–90% accuracy.

## Limitations of This Research

This article is a review and commentary rather than a new clinical study, so its conclusions are based on the available published literature at the time of writing (January/February 2017). Several important limitations should be noted:

- The number of long-term studies on psychological outcomes of DTC genomics testing is limited, and most studies are relatively short-term.
- Current users of DTC genomics services like 23andMe tend to be more affluent, educated, and emotionally prepared than the general population, so results may not generalize to all patients.
- Most studies on behavior change after genetic risk disclosure have used self-reported outcomes, which may be unreliable.
- The landscape of DTC genomics companies and their services changes rapidly; the company list and evidence cited reflect June 2016.
- There is no proven medical intervention for some conditions tested, such as Alzheimer's disease, which may limit the clinical utility of risk information.

## Recommendations for Patients

Based on the evidence presented in this article, patients may wish to consider the following guidance when deciding whether to use direct-to-consumer genomics testing:

1.
**Think about why you want the test.** If you are seeking ancestry information or benign traits, the stakes are low. If you are seeking health risk information, be aware that for most complex diseases, the predictions are not clinically definitive.
1.
**Consider speaking with a genetic counselor before testing.** Pre-test counseling can help you prepare for possible adverse news, especially for conditions like Huntington disease where no mitigating therapies exist.
1.
**Read the terms of service carefully.** Understand that companies like 23andMe explicitly state their tests are not designed to independently diagnose, prevent, or treat any condition, and that they make no warranty that results will be accurate or reliable.
1.
**Bring your results to a doctor or genetic counselor for interpretation.** A genetically literate physician can help you understand what your results do—and do not—mean for your health.
1.
**Do not make major medical decisions based on DTC results alone.** Any clinically significant response, such as seeking a mastectomy or ovariectomy, will and should require physician intermediation.
1.
**Remember that lifestyle matters regardless of your genes.** For diabetes and heart disease, most people don't need test data to know that a better diet and regular exercise will improve their health.
1.
**Be cautious about online diagnostic tools.** Given that symptom checkers are correct only about 43% of the time, they should not replace professional medical evaluation.
1.
**Weigh the privacy implications.** Genetic information, once known, cannot be "un-known," and may have implications for insurance declarations and other third-party interests.

## Frequently Asked Questions

### Will learning my genetic risk for diseases like Alzheimer's or cancer cause lasting psychological harm?

Studies show no lasting harm. In a study of 162 adults tested for the ApoE4 Alzheimer's risk gene, disclosure caused only transient, modest distress in those with the risk variant and benefit in those without it. Cancer risk results increased risk perception but did not produce lasting anxiety. However, preparation and counseling are still recommended.

### If my direct-to-consumer genetic test says I have an elevated risk for heart disease or diabetes, can I trust the prediction?

For most complex diseases like heart disease, diabetes, and depression, the clinical validity of gene-based predictions is weak or nonexistent. A study comparing three DTC companies found significant variation in risk predictions for the same diseases. Genetic risk is not destiny; for example, only about 20% of people with two APOL1 risk copies develop kidney disease.

### Will knowing my genetic risk motivate me to exercise more or quit smoking?

Probably not. A review of 14 studies found that communicating DNA-based disease risk estimates has little or no effect on smoking and physical activity. This is similar to typical doctor's advice without genetic testing. So while genetic information may be interesting, it is unlikely to change health behaviors on its own.

### I got my genome sequenced and found mutations that disrupt genes. Should I be worried?

No, not automatically. A 2012 analysis of 185 healthy genomes found that the typical healthy person has about 100 loss-of-function mutations, with about 20 affecting both gene copies. Most of these are in non-essential genes and are not linked to common diseases. Simply having such variants is not a reason to seek medical intervention.

### Can I order a genetic test without involving my doctor?

Yes, most direct-to-consumer genetic testing companies work directly with consumers without a doctor's order. However, the article recommends speaking with a genetic counselor before testing and bringing results to a doctor or genetic counselor afterward for interpretation. This helps prepare for adverse news and understand what results really mean.

### My genetic testing company gives me a risk score for a disease. Will another company give the same result?

Not necessarily. A study comparing three direct-to-consumer genomics companies assessing risk for six common diseases found that their analyses varied significantly in predictive ability and in the risks predicted for individual consumers. Therefore, your risk estimate may differ depending on the company, and these predictions are not clinically definitive.

### What happens to my genetic data after I send in my saliva sample?

Companies like 23andMe collect genetic data to identify patterns and aggregate information to sell to researchers, insurers, and pharmaceutical companies. This business model subsidizes the low cost to consumers. Also, the company's terms of service state their tests are not designed to diagnose, prevent, or treat any condition and make no warranty of accuracy.

### Should I get a second opinion before making medical decisions based on my home DNA test results?

Direct-to-consumer genetic test results are not clinically definitive for most complex diseases, and different companies may give different risk predictions for the same condition. Since genetic risk is not destiny, major medical decisions such as mastectomy or ovariectomy should involve a physician. A second opinion from a genetically literate physician or genetic counselor can help interpret what your results do and do not mean for your health. Diagnostic Detectives Network provides independent expert second opinions.

## Source Information

This patient-friendly article is based on the following peer-reviewed research:

**Original Article:** "Direct-to-Consumer Genomics: Harmful or Empowering?"

**Author:** Joel C. Eissenberg, PhD

**Journal:** Missouri Medicine (science of Medicine section)

**Publication Details:** January/February 2017, Volume 114, Issue 1, pages 26–31

Adapted from: [https://www.genome.gov/27565109/the-cost-of-sequencing-a-human-genome/](https://www.genome.gov/27565109/the-cost-of-sequencing-a-human-genome/) (Figure 1 source); [http://revenuesandprofits.com/how-23andme-makes-money-understanding-23andme-business-model/](http://revenuesandprofits.com/how-23andme-makes-money-understanding-23andme-business-model/) (Figure 2 source); [http://isogg.org/wiki/List_of_personal_genomics_companies](http://isogg.org/wiki/List_of_personal_genomics_companies) (Table I source); Nuffield Council on Bioethics (2010), "Medical Profiling and Online Medicine: The Ethics of Personalised Healthcare," NCB, London, Chapter 3 (Table II source).

*Note: This patient-friendly summary was written to make the original research accessible to a general audience. It does not constitute medical advice. Patients with questions about genetic testing should consult their physician or a genetic counselor.*


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