Category: 1. Direct-to-Consumer Genetic Testing

Learn more from MedlinePlus Genetics about some of the health conditions and traits that may be included in your report. Each plain-language summary provides information about the condition’s major features, frequency, causes, and inheritance. You will also find links to other reputable sources of online health information.

Health conditions

BRCA1– or BRCA2-related breast cancer and ovarian cancer  

Familial adenomatous polyposis, including MUTYH-associated polyposis

Age-related macular degeneration  

Alpha-1 antitrypsin deficiency

Celiac disease           

Familial hypercholesterolemia

Glucose-6-phosphate dehydrogenase deficiency, also called G6PD deficiency

Hereditary hemochromatosis

Transthyretin amyloidosis

Hereditary thrombophilia: prothrombin thrombophilia and factor V Leiden thrombophilia     

Alzheimer disease  

Parkinson disease

Wellness

Lactose intolerance

Traits

Cheek dimples

Eye color

Hair texture

Hair color (light or dark hair)

Carrier status

Autosomal recessive spastic ataxia of Charlevoix-Saguenay, also called ARSACS

Andermann syndrome, also called agenesis of the corpus callosum with peripheral neuropathy

Polycystic kidney disease

Beta thalassemia     

Bloom syndrome    

Canavan disease

PMM2-congenital disorder of glycosylation, also called PMM2-CDG

Cystic fibrosis            

D-bifunctional protein deficiency

Dihydrolipoamide dehydrogenase deficiency             

Familial dysautonomia          

Congenital hyperinsulinism, also called familial hyperinsulinism

Familial Mediterranean fever

Fanconi anemia       

GRACILE syndrome

Gaucher disease

Glycogen storage disease type I        

Hereditary fructose intolerance        

Junctional epidermolysis bullosa

Leigh syndrome       

Limb-girdle muscular dystrophy       

Medium-chain acyl-CoA dehydrogenase deficiency, also called MCAD deficiency

Maple syrup urine disease  

Mucolipidosis type IV            

CLN5 disease, also called neuronal ceroid lipofuscinosis (CLN5-related)

CLN1 disease, also called neuronal ceroid lipofuscinosis (PPT1-related)    

Niemann-Pick disease           

Nijmegen breakage syndrome

Nonsyndromic hearing loss 

Pendred syndrome

Phenylketonuria

Primary hyperoxaluria        

Pyruvate kinase deficiency 

Rhizomelic chondrodysplasia punctata

Sialic acid storage disease, including Salla disease

Sickle cell disease, also called sickle cell anemia   

Sjögren-Larsson syndrome 

Tay-Sachs disease

Tyrosinemia              

Usher syndrome     

Zellweger spectrum disorder, also called Zellweger syndrome spectrum

Pharmacogenetics

CYP2C19 drug metabolism

Passed in 2008, a federal law called the Genetic Information Nondiscrimination Act (GINA) made it illegal for health insurance providers in the United States to use genetic information in decisions about a person’s health insurance eligibility or coverage. This means that health insurance companies cannot use the results of a direct-to-consumer genetic test (or any other genetic test) to deny coverage or require you to pay higher premiums. However, GINA does not apply when an employer has fewer than 15 employees.

GINA does not apply to other forms of insurance, such as disability insurance, long-term care insurance, or life insurance. However, some states have laws that cover these forms of insurance. Unless prohibited by state laws, companies that offer these policies have the right to request medical information, including the results of any genetic testing, when making decisions about coverage and rates. Some of these companies request information about genetic testing as part of their application process, but others do not. It is unclear whether genetic information, including the results of direct-to-consumer genetic testing, will become a standard part of the risk assessment that insurance companies undertake when making coverage decisions.

You should weigh the possible benefits and risks of direct-to-consumer genetic testing, including potential impacts on insurance eligibility and coverage, before you start the testing process.

A person’s genetic data represent personal, private health information. If you are considering direct-to-consumer genetic testing, it is important to know how the testing company will protect your information. In particular, you should know how the company will handle your sample (for example, saliva), how it plans to safeguard your data, and whether and how your data will be used for secondary purposes (such as research or advertising).

Most direct-to-consumer genetic testing companies provide detailed information on their websites about their privacy and security practices. This information may be included in a “privacy policy,” “privacy statement,” or “privacy center.” Be sure to read, understand, and agree with this information before you start the testing process. If you have questions, contact the company to get more information.

Questions that can help you assess a company’s privacy practices include:

• What does the company do with your sample once it has completed the analysis? Will the sample be stored, shared, sold, or destroyed?
• Once you take the test, who owns your genetic data?
• How does the company safeguard your genetic data and other personal information that you provide? Is it stored in a database that is protected from unauthorized access? What happens if the database is hacked or otherwise compromised?
• Can you delete your results from the company’s database if you wish?
• Does the company use your information for internal research, advertising, or other secondary purposes?
• Will the company share your genetic data or sell it to pharmaceutical or biotechnology companies, academic institutions, or nonprofit organizations? If so, will the shared data include other information that could identify you (such as your name or date of birth)? For what purposes will your data be used? Will you be informed when your data are shared or sold?
• If you do not want your genetic data shared, sold, or used for research, can you opt out? What happens if you agree to share your information but want to opt out later?
• Will you be notified in the future if the company changes its privacy policies?
• What would happen to your sample and your genetic information if the company is sold or goes out of business?

In some cases, even if a testing service promises not to share your genetic information with others, they may be required by law to disclose the information to authorities in response to a warrant, court order, or other legal requirement. Many companies now provide explicit information about whether and how your genetic data may be accessed by law enforcement officials. If you upload your data to public databases, such as those administered by some third-party interpretation services, that information will be available to law enforcement. Be sure to read and understand how your data may be accessed by authorities before you submit your sample. Because everyone shares genetic similarities with their relatives, it may have implications not only for your own privacy but for that of people who are related to you.

Several direct-to-consumer genetic testing companies report how much DNA a person has inherited from prehistoric humans, such as Neanderthals and Denisovans. This information is generally reported as a percentage that suggests how much DNA an individual has inherited from these ancestors. The percentage of Neanderthal DNA in modern humans is zero or close to zero in people from African populations, and is about 1 to 2 percent in people of European or Asian background. The percentage of Denisovan DNA is highest in the Melanesian population (4 to 6 percent), lower in other Southeast Asian and Pacific Islander populations, and very low or undetectable elsewhere in the world.

Neanderthals were very early (archaic) humans who lived in Europe and Western Asia from about 400,000 years ago until they became extinct about 40,000 years ago. Denisovans are another population of early humans who lived in Asia and were distantly related to Neanderthals. (Much less is known about the Denisovans because scientists have uncovered fewer fossils of these ancient people.) The precise way that modern humans, Neanderthals, and Denisovans are related is still under study. However, research has shown that modern humans overlapped with Neanderthal and Denisovan populations for a period, and that they had children together (interbred). As a result, many people living today have a small amount of genetic material from these distant ancestors.

Scientists have sequenced Neanderthal and Denisovan genomes from fossils discovered in Europe and Asia. This genetic information is helping researchers learn more about these early humans. Determining which areas of the genome are shared with archaic humans, and which areas are different, will also help researchers find out what differentiates modern humans from our closest extinct relatives.

In addition to the percentage of Neanderthal or Denisovan DNA, direct to-consumer testing reports may include information about a few genetic variants inherited from these ancestors that influence specific traits. Some studies have suggested that certain genetic variations inherited from archaic humans may play roles in hair texture, height, sensitivity of the sense of smell, immune responses, adaptations to high altitude, and other characteristics in modern humans. These variations may also influence the risk of developing certain diseases. However, other studies have not found the same associations. The significance of Neanderthal or Denisovan genetic variants on disease risk is still an area of active study, and most direct-to-consumer test results currently do not include them.

While knowing how much DNA a person has in common with his or her Neanderthal or Denisovan ancestors may be interesting, these data do not provide practical information about a person’s current health or chances of developing particular diseases. Having more or less DNA in common with archaic humans says nothing about how “evolved” a person is, nor does it give any indication of strength or intelligence. For now, knowing which specific genetic variants a person inherited from Neanderthal or Denisovan ancestors provides only limited information about a few physical traits.

While a direct-to-consumer genetic test can estimate your risk, it cannot tell you for certain whether you will or will not develop Alzheimer disease. Variations in multiple genes, together with lifestyle factors such as diet and exercise, all play a role in determining a person’s risk.

The U.S. Food and Drug Administration (FDA) has allowed at least one direct-to-consumer genetic testing company, 23andMe, to offer a test for Alzheimer disease risk. The test analyzes a gene called APOE. Certain variations in this gene are associated with the likelihood of developing late-onset Alzheimer disease (the most common form of the condition, which begins after age 65). Specifically, the test allows you to find out how many copies (zero, one, or two) you have of a version of the gene called the e4 allele. People who have zero copies of the e4 allele have the same risk of late-onset Alzheimer disease as the general population. The risk increases with the number of copies of the e4 allele, so people with one copy have an increased chance of developing the disease, and people with two copies have an even greater risk. However, many people who have one or two copies of the e4 allele never develop Alzheimer disease, and many people with no copies of this allele ultimately get the disease.

Variations in the APOE gene are among many factors that influence a person’s overall risk of developing Alzheimer disease. Variations in many other genes, which are not reported in the FDA-approved direct-to-consumer genetic test, also contribute to disease risk. Additionally, there are risk factors for Alzheimer disease that have yet to be discovered. Therefore the APOE e4 allele represents only one piece of your overall Alzheimer disease risk.

Currently, there are no effective approaches for preventing Alzheimer disease, and while the disease can be treated, it has no cure. For these reasons, the National Institute on Aging and patient advocacy groups strongly recommend that people considering genetic testing for Alzheimer disease, including direct-to-consumer genetic testing, talk with a doctor or genetic counselor about the reasons they want to undergo testing and how they would cope with the results.

While a direct-to-consumer genetic test can estimate your risk, it cannot tell you for certain whether you will or will not develop certain forms of cancer. Many other factors, including sex, age, diet and exercise, ethnic background, a history of previous cancer, hormonal and reproductive factors, and family history also contribute to a person’s overall cancer risk.

The U.S. Food and Drug Administration (FDA) has allowed at least one direct-to-consumer genetic testing company, 23andMe, to offer a test for cancer risk. The test identifies specific genetic changes that are associated with particular cancers. For example, it looks for three specific genetic variants (also known as mutations) in two genes: BRCA1 and BRCA2. These variants are associated with an increased risk of breast cancer, ovarian cancer, and potentially other forms of cancer in people of Ashkenazi (eastern European) Jewish ancestry.

Researchers estimate that 5 to 10 percent of all cancers run in families. Some of these cancers are associated with inherited mutations in particular genes, such as BRCA1 or BRCA2. More than 1,000 variants in each of these genes have been associated with an increased risk of cancer. However, the FDA-approved direct-to-consumer genetic test analyzes only three of these genetic changes. The variants included in the test are much more common in people of Ashkenazi Jewish background than in people of other ethnicities, so if you are not of Ashkenazi Jewish heritage, the results may not be useful to you.

The test offered by 23andMe also looks for two variants in the MUTYH gene. These variants can cause a condition called MUTYH-associated polyposis (MAP; also known as autosomal recessive familial adenomatous polyposis). MAP greatly increases a person’s risk of  developing colorectal cancer, but it accounts for less than 1 percent of colorectal cancer cases. The two variants included in the test are the most common MAP-associated changes in people of European descent; however there are more than 100 variants in the MUTYH gene known to be associated with an increased risk of developing cancer.

Because the variants included in these tests are uncommon, most people will have a negative result. A negative result does not mean that you will never get cancer. Similarly, a positive result (one that indicates a cancer-related genetic variation) does not mean that you will definitely develop cancer.

Direct-to-consumer genetic testing for cancer risk can be stressful and anxiety-producing. Health professional organizations and patient advocacy groups strongly recommend that people considering genetic testing for cancer-associated gene variants, including those included in direct-to-consumer genetic tests, talk with a genetic counselor about the reasons they want to undergo testing and what the results could mean for their health.

In addition to providing various reports and analyses based on your genetics, some direct-to-consumer genetic testing companies make your raw data available to download. The raw data are your genotype—the particular A’s, C’s, T’s, and G’s of your DNA—extracted from the sample you provided. These data are unique to you. Most companies caution that the raw data are only for research or education and are not suitable for medical purposes, such as diagnosing a disease.

It is challenging to interpret raw genotype data on your own. To help with this, several online “third-party interpretation” services offer analysis and interpretation of the raw data collected by another company. Third-party interpretation services can potentially use your genetic data to provide you with more information about your disease risk, traits, and ancestry. However, these services also have some risks and limitations:

• Relatively often, test results indicate an increased risk of disease when your risk is not actually higher than that of the general population. These errors can cause stress and anxiety.
• The results may include unexpected or upsetting information about your disease risk or family relationships without any context or guidance.
• The raw data, once you download it and send it by e-mail or store it on your computer, is no longer protected by the original service’s privacy measures.
• There is little regulation of third-party interpretation services.

As with any kind of genetic testing, it is important to assess the credibility of any company you are considering and find out how it protects your privacy before submitting your genetic information. Your healthcare provider can help you understand your results and determine whether any follow-up testing would be useful.

Direct-to-consumer genetic testing can provide interesting information about your health, traits, and ancestry. However, the results may not be  clear-cut. Companies that provide these tests often tell their customers that the results are for information, education, and research purposes only—they are not meant to diagnose, prevent, or treat any disease or health condition. It is useful to keep this distinction in mind when interpreting your own test results.

Health and disease risk

The results of these genetic tests provide information about your chance of developing certain diseases (such as celiac disease or Parkinson disease) and the likelihood that you have particular traits (such as dimples or lactose intolerance). These tests may also provide information about how a person may respond to certain drugs (pharmacogenomics). Test results are usually based on an analysis of one or more genetic variations that are known or suspected to be associated with the disease or trait. Direct-to-consumer genetic tests do not look at all genetic variants associated with diseases or traits.

The results of tests to predict disease risk do not provide a “yes or no” answer about whether a person will develop a given disease. Other factors, including genetic variations that were not tested, environmental factors, and lifestyle choices (such as diet and exercise) also contribute to disease risk in ways that may not be fully understood. Therefore, a result showing an increased risk does not mean you will definitely develop the disease, and a result showing a reduced risk does not mean you will never develop the disease.

Ancestry or genealogy

The results of these tests give clues about major geographic areas that are your family’s origins. These results are calculated on the basis of genetic variations that are more common in people from certain areas of the world than in others. 

Sometimes the results of ancestry testing are unexpected or inconsistent with what a person understands about his or her family history. People who are closely related, such as siblings, may receive slightly different information about their ancestry because results are limited by the number and diversity of people who have submitted DNA samples to a given direct-to-consumer genetic testing company. It is important to be aware that receiving unexpected or ambiguous information about your background is a potential risk with this type of testing.

Kinship

The results of these tests give information about individuals who are likely related to you. (These individuals have also undergone testing, and the predictions are based on similarities among DNA sequences.) These tests can uncover previously unknown information about biological relationships among people (such as paternity). It is important to be aware that receiving unexpected or ambiguous information about your background or family is a potential risk with this type of testing.

Lifestyle

In most cases, direct-to-consumer lifestyle tests assess genetic variations related to very specific traits, such as how your body converts the nutrients from food into energy (metabolism), day/night (circadian) rhythm, or the senses of taste and smell. The company may recommend specific diet or fitness programs, dietary supplements, skincare products, or other products and services on the basis of your results. However, in most cases the link between a given genetic variation and a complex trait like weight, athletic performance, or sleep is indirect or unknown. Therefore, the results of these tests can be challenging to interpret, and it can be difficult to predict whether a recommended product or service will be helpful to you.

If you have questions about the meaning of your test results, professional support (such as guidance from a genetic counselor) may be available from the company that provided the test. You can also share questions about your results with your own healthcare provider. Talk to your doctor before making any major changes in managing your health, diet, or fitness after you receive results of a direct-to-consumer genetic test.

The price of direct-to-consumer genetic testing ranges from under a hundred dollars to thousands dollars. The cost depends on how many genetic variations are analyzed (and it will cost more if whole genome or whole exome sequencing is used), how extensive the interpretation of results is, and whether other products, programs, or services are included. Some companies charge separately for the sample collection kit and the analysis, while others offer the sample collection and analysis as part of a package. In some cases, consultation with a healthcare professional (such as a genetic counselor) is included in the cost of testing; in others, it can be added for an additional fee. Before you proceed with testing, make sure you know the total cost for all of the results, support, and other services you expect to receive.

Direct-to-consumer genetic tests, even tests that provide information about health and disease risk, are not covered by most health insurance plans. Because this testing is done without a referral from a healthcare provider and is not considered “diagnostic” (that is, it cannot be used to diagnose any disease or condition), health insurance companies generally will not pay for it. However, the tests may be eligible for reimbursement through flexible spending accounts (FSA) or health spending accounts (HSA) if the testing included health information. If you decide to share your results with your healthcare provider and he or she recommends additional testing or management, that follow-up care may be covered by insurance.

Direct-to-consumer genetic tests that are unrelated (or indirectly related) to health, such as ancestry testing and paternity testing, are typically not covered by FSAs, HSAs, or health insurance plans.

For most types of direct-to-consumer genetic testing, the process involves:

1. Purchasing a test

Test kits can be purchased online (and are shipped to your home) or at a store.  The price of some test kits includes the analysis and interpretation, while in other cases this information is purchased separately.

2. Collecting the sample

Collection of the DNA sample usually involves spitting saliva into a tube or swabbing the inside of your cheek and putting that swab into a tube. You then mail the sample as directed by the company. In some cases, you will need to visit a health clinic to have blood drawn.

3. Analyzing the sample

A laboratory will analyze the sample to look for particular genetic variations. The variations included in the test depend on the purpose of the test.

4. Receiving results

In most cases, you will be able to access your results on a secure website or app. (You will likely need to create an account on the testing company website to access results.) Other test companies share results in the mail or over the phone. The results usually include interpretation of what specific genetic variations may mean for your health or ancestry. At some companies, you can request additional explanation from a genetic counselor or other healthcare provider. This additional service may or may not involve an extra cost. Some testing companies may update your results over time based on new scientific information, such as a new genetic variant associated with a trait on their test.