Genetic testing, including ancestry testing, has increased in popularity in recent years thanks to direct-to-consumer genetic testing kits. In the past, consumers had to go through healthcare providers for any type of genetic testing. Now, anyone can order an inexpensive DNA test online from one of several genetic testing companies.
In 2018 alone, over 12 million people. This number is expected to grow as public interest in personal health and ancestry flourishes. But are at-home genetic testing kits all they’re cracked up to be? While these tests may provide valuable information, they also have limitations that may actually harm consumers.
“Many at-home screening kits do ancestry testing, and some also do disease and carrier testing. But it’s important to remember that these types of kits vary. Depending on the genetic testing company and the services they provide, a person could be left to interpret and deal with the results on their own,” says Karen Grinzaid, Executive Director of the JScreen program and Assistant Professor in the Department of Human Genetics at Emory University School of Medicine. JScreen, a nonprofit educational and genetic screening program, offers individuals information about their carrier risk for many genetic diseases, including Gaucher disease.
Direct-to-Consumer Genetic Testing
Today, consumers have access to a variety of at-home genetic testing kits. Depending on the type of kit used, at-home genetic testing kits may provide information about:
- Disease risk and health
With all at-home testing kits, individuals receive a specimen collection device and mail in a sample, usually saliva, for analysis at a genetic testing company. The companies providing these kits all differ. Some companies provide a medical review of test results and genetic counseling services, while others do not offer any interaction with medical professionals or genetic counselors.
Are At-Home Genetic Testing Kits Accurate?
Many people wonder whether direct-to-consumer kits are as accurate as other genetic tests, such as those performed in healthcare facilities. “When it comes to carrier screening, it really depends on the test a laboratory performs,” says Grinzaid. “DNA sequencing technology offers a detailed look at the disease genes on a screening panel. These tests are very accurate in identifying carriers for those genetic diseases.”
“But some laboratories use different technologies, such as genotyping, which only identifies common changes in genes. Since the results aren’t based on examination of the entire gene, consumers won’t get as high a carrier detection rate,” says Grinzaid.
Other technologies, such as single nucleotide polymorphism (SNP) technology, identify changes to nucleotides, the building blocks of DNA. But the results generally don’t provide very accurate disease or carrier risk assessment. Instead, these results may be more beneficial for helping scientists simply locate genes associated with specific diseases. Ancestry testing often uses SNP technology.
At-Home Genetic Testing and Gaucher Disease
Some people view at-home genetic testing kits as a definitive method for determining whether or not they’re at risk for developing certain genetic diseases. Others may believe that all direct-to-consumer kits accurately predict their likelihood of passing on genetic mutations that lead to disease development.
But it’s not as easy as that. Scientists associate Gaucher disease with over 400 genetic mutations, but some direct-to-consumer test kits may not detect all of these mutations. Having even one of these mutations makes a person a Gaucher disease carrier, capable of passing on the abnormal gene to future offspring. For certain populations, especially Ashkenazi Jews who are at higher risk, a person’s Gaucher disease carrier status can be critically important for family planning and disease risk assessment.
Direct-to-Consumer Genetic Testing Pros and Cons
Like any product, there are benefits and disadvantages to using genetic testing and ancestry kits.
What Are the Benefits of Using an At-Home Genetic Testing Kit?
“If you use a kit that performs genetic testing using DNA sequencing on the Gaucher disease genes, you’ll get a really good assessment of the gene. Within the Ashkenazi Jewish population, approximately eight genetic mutations in the Gaucher gene account for about 95% of carriers. So Ashkenazi Jews who do an at-home genotyping test looking for those specific mutations only have pretty good success determining whether that individual was a Gaucher disease carrier or was affected by the disease,” says Grinzaid. “But if you’re testing someone who does not have an Ashkenazi Jewish background, the carrier detection rate is much lower.”
Regardless of a person’s ancestry, there may be benefits to using direct-to-consumer genetic testing kits. Many use their results for entertainment, or to learn new information about their background. For some, this might mean identification of an ethnic background that wasn’t previously known. If someone learns they are of Ashkenazi Jewish descent, it may encourage them to pursue further screening for diseases commonly occurring in Ashkenazi Jews, like Gaucher disease. At JScreen, a Jewish genetic disease carrier screening program, the majority of genes on the screening panel are sequenced, but given the complexity of sequencing that gene, genotyping is used for Gaucher testing. If someone has non-Jewish background, a family history of Gaucher disease, or is at risk for the disease, JScreen’s genetic counselors help facilitate sequencing of that gene when indicated.
Regardless of a person’s ancestry, there may be benefits to using direct-to-consumer genetic testing kits. Many use their results for entertainment, or to learn new information about their background. For some, this might mean identification of an ethnic background that wasn’t previously known. If someone learns they are of Ashkenazi Jewish descent, it may encourage them to pursue further screening for diseases commonly occurring in Ashkenazi Jews, like Gaucher disease.
Additionally, finding out a person is of Jewish heritage can be especially beneficial for those displaying symptoms of Gaucher disease, particularly if they haven’t been officially diagnosed. Results indicating a Jewish background may confirm a doctor’s suspicions and help point them in the right direction to test specifically for Gaucher disease.
What Are the Pitfalls of Using an At-Home Genetic Testing Kit?
But direct-to-consumer genetic testing kits aren’t without their limits. In the majority of cases, consumers receive no follow-up counseling to help them interpret their results. Many companies leave consumers to cope with their results independently, which may result in delayed or avoided treatment for potential problems.
“Let’s say you get your results about your risk for heart disease. Your results show that your risk is 1.5 times higher than it was previously. It’s an increased risk, but what does this actually mean? Is it really significant? What kind of lifestyle changes should you make based on your results? Many people may view their results as dramatic when they aren’t, and vice versa. It’s a tricky situation,” says Grinzaid.
Another example involves the BRCA gene. Mutations in this gene are associated with increased risks for breast, ovarian, prostate and pancreatic cancers. If a person’s direct to consumer test results indicate they have a BRCA mutation, how accurate are those results? Should they schedule a mastectomy immediately?
“Recently, a direct-to-consumer company started reporting BRCA results, but their testing only looks for three common genetic changes in these genes that are frequently found in the Ashkenazi Jewish population. “If you test positive for a BRCA mutation through this company, you still need follow-up confirmatory testing through a healthcare professional before making any decisions about your healthcare,” explains Grinzaid. “There are also thousands of other changes in these and other genes that are related to an increased risk for breast and ovarian cancer, so a negative test for these three mutations does not eliminate your risk for cancer.”
Additionally, many genetic testing companies don’t take family history into account. A person may have a family history of Gaucher disease, but if their test results aren’t concerning, they may not seek any additional follow-up. The person receiving the results may not be tested for the mutations occurring specifically within their family.
What is the Role of Genetic Counselors?
Genetic counselors, such as those working with JScreen, receive special training to interpret genetic test results. Counselors speak with individuals undergoing genetic testing to discuss their results, suggest next steps if necessary, and counsel about the risks of passing down genetic mutations to future generations.
Many genetic counselors meet regularly with clients over the phone or through video chat. They also help identify persons at risk for genetic diseases like Gaucher disease and connect them with other resources for follow-up testing or Gaucher disease care.
Genetic counselors often refer at-risk individuals to the National Gaucher Foundation (NGF). NGF’s Optimal Health Initiative connects individuals at risk for or living with Gaucher disease with specialists and other resources to help them stay as healthy as possible. The Optimal Health Advisors, who are licensed clinical social workers (LCSWs), work in tandem with genetic counselors .
The Importance of Genetic Counseling
“Genetic counseling is extremely important, and people should go into genetic testing with as much information as possible. People need a qualified counselor who understands their results, and who can also connect them to specialists, like Gaucher specialists, for further evaluation if necessary. People may not take a careful look or may overinterpret their results without access to genetic counselors to help explain them,” says Grinzaid.
“As these direct-to-consumer tests grow in popularity, companies should ideally incorporate genetic counseling into their services. The good thing about these tests being out there is that there’s increased awareness of genetics. They can encourage a person to be proactive about their health. I also think the tests that are out there now are only going to get better and provide more information. These tests may give people a heads-up about potential problems that they would never have known about previously,” says Grinzaid.
- Centers for Disease Control and Prevention. Consumer Genetic Testing is Booming: But What are the Benefits and Harms to Individuals and Populations? https://blogs.cdc.gov/genomics/2018/06/12/consumer-genetic-testing/
- S. National Library of Medicine. What kinds of direct-to-consumer genetic tests are available? https://ghr.nlm.nih.gov/primer/dtcgenetictesting/dtctesttypes
- S. National Library of Medicine. What are single nucleotide polymorphisms (SNPs)? https://ghr.nlm.nih.gov/primer/genomicresearch/snp
- National Gaucher Foundation. Gaucher Disease Carrier Status. https://www.gaucherdisease.org/gaucher-diagnosis-treatment/testing/carrier/
- National Gaucher Foundation. Genetic Carrier Screening. https://www.gaucherdisease.org/genetic-carrier-screening/