Direct-to-consumer genetic testing provides a view into an individual’s DNA, offering information connected to health and ancestry. Companies analyze a saliva sample to generate reports about genetic predispositions for various health-related topics. This process identifies specific variations in a person’s genetic code to illuminate how genetics may influence the likelihood of developing certain conditions. These reports provide insights that were once only accessible through clinical settings.
Genetic Health Risk Reports
Genetic health risk reports indicate if a person has specific genetic variants associated with a higher chance of developing certain health conditions. These reports show a predisposition, not a definitive diagnosis. Having a variant linked to a disease does not guarantee that an individual will develop it, as many other factors, including lifestyle and environment, also play a part. The information is about statistical risk, not a predetermined outcome.
Among the most well-known reports are those for Late-Onset Alzheimer’s Disease, where the test looks for variants in the APOE gene, and Parkinson’s Disease, which screens for variants in the LRRK2 and GBA genes. The service also provides reports on conditions like Celiac Disease, an immune reaction to eating gluten. Another report is for hereditary hemochromatosis, a disorder that causes the body to absorb too much iron.
Another area covered is hereditary cancer risk, specifically for certain variants in the BRCA1 and BRCA2 genes linked to a higher risk of breast, ovarian, and prostate cancers. The 23andMe test only screens for three specific variants common in people of Ashkenazi Jewish descent, not the thousands of BRCA variants that can increase cancer risk. A result showing no variants detected does not eliminate the possibility of having other risk-increasing mutations.
Carrier Status Reports
Carrier status reports focus on inherited conditions where an individual “carries” one genetic variant but does not show symptoms. These recessive disorders require two copies of the variant for the condition to manifest. Being a carrier means there is a chance of passing the genetic variant to a child. If both parents are carriers for the same condition, their child has a 25% chance of inheriting two copies and having the disorder.
This information is relevant for family planning, allowing prospective parents to understand their chances of passing on a genetic condition. The reports cover over 40 inherited conditions. Some of the conditions included are:
- Cystic Fibrosis, a disorder that causes severe damage to the lungs and digestive system.
- Sickle Cell Anemia, a blood disorder that affects hemoglobin.
- Tay-Sachs Disease, a rare disorder that destroys nerve cells in the brain and spinal cord.
- Gaucher Disease Type 1, an inherited metabolic disorder.
Understanding carrier status for these conditions can inform conversations with a partner and a healthcare provider about reproductive options and potential risks for future children.
Pharmacogenetics and Wellness Insights
Genetic testing can offer insights into how an individual’s body may process certain medications. These pharmacogenetics reports analyze DNA to predict potential responses to specific drugs. This information is a starting point for discussions with a healthcare provider about medication choices and is not a guide for self-prescribing or changing dosages.
The service also includes “Wellness” reports that cover non-disease traits influenced by genetics. These reports provide information on topics like Lactose Intolerance, explaining how genetics can affect the digestion of dairy products. Other wellness reports explore predispositions related to sleep patterns and physical traits like muscle composition.
Understanding the Limitations
It is important to recognize the limitations of direct-to-consumer genetic tests, which are screening tools, not diagnostic tests. A screening test identifies potential health risks or carrier status but cannot diagnose a condition. A diagnosis requires confirmation from a healthcare provider, often involving further testing in a clinical setting.
A significant limitation is that these tests are not exhaustive. As seen with the BRCA test, the screening may only look for a few specific variants out of thousands known to be associated with a disease. A result of “no variant detected” means only that the specific variants tested for were not found. It does not rule out the presence of other variants that could increase risk.
The relevance of some genetic information can be influenced by an individual’s ethnicity, as certain genetic variants are more common in specific populations. The risk calculations may be most accurate for those groups. While the tests analyze tens of thousands of variants, this is a small fraction of the millions in the human genome, meaning the scope is targeted and not a complete genetic analysis.
Interpreting Your Health Results
Receiving genetic health information can be complex, and you should not make health decisions based solely on these reports. The results are a starting point for a more informed conversation about your health. Any concerning findings should be discussed with a healthcare professional, such as a doctor or a certified genetic counselor.
A healthcare provider can help put the results into the context of your overall health, family history, and lifestyle. They can also order confirmatory diagnostic testing from a clinical laboratory. This step verifies the initial screening result before any medical decisions are made.
These professionals can also help navigate the emotional impact of receiving this information. Learning about a predisposition for a serious condition or a carrier status for a genetic disorder can be stressful. A genetic counselor can provide support and guidance, helping you understand the information and make informed choices about your health and family planning.