What is genetic testing?
Rather than diving into scientific terminology to explain genetic testing, let’s start with an analogy of building a house to describe a person’s DNA. DNA is the blueprint for building all the functional cells, tissues, organs in an organism as well as coordinating all the functions.
The first step to building a house is to create a blueprint which the builder uses as a guide. Let’s say the architect forgot to draw the stairs and nobody proof-reads the blueprint for errors. Then we have a house without stairs. How does one get from one floor to the other? One can install an elevator, but in case of a serious fire hazard the elevator would shut down and occupants left without an escape route. Similarly, an organism with errors (mutations) in its blueprint (DNA) can be ‘built’ but it may crash under conditions of stress or illness.
Why this is relevant to you? If you are planning to have children, you know it is necessary to copy your DNA blueprint and pass it on to your offspring. If cells from either parent have any information that is missing or corrupted, the child has an increased chance of inheriting a disease as a result of this error. Besides, understanding your DNA blueprint can give you insights to health issues you have experienced and explain the odd reactions you have had to specific medications.
Is there a way to avoid genetic diseases?
Just like an architect hires an assistant to double check the blueprints of a house, you can buy a genetic test to proof-read your DNA for genetic errors (mutations) before having children.
There are several companies which test your DNA, to identify your ancestry, ensure your health status, assess the risk of passing on genetic diseases to your offspring and some even claim to predict your life span. Interestingly, it is not uncommon to find the word ‘DNA” being used in unrelated businesses – cosmetic companies selling “custom formulated face-creams based on your DNA” or a holistic healer advertising “12-stranded DNA activation” and “replacement of 6 genes that involve depression, anger and anxiety” or spas advertising “DNA reprogramming” to achieve youthful vitality.
It can get confusing.
This post aims to:
- Provide you with the knowledge necessary to choose the best genetic testing option for you and your family
- Understand the different technologies used in DNA testing
- Help you through a genetic testing process
You can use several “checkpoints” to evaluate the genetic test
There are two major types of technology used in genetic testing
SNP genotyping which analyzes your DNA to identify only known gene variations
DNA sequencing which identifies known and new gene variations
Which genetic testing technology is best for me?
It depends on your reason for having a genetic test.
Choose SNP genotyping if you wish to know whether you carry the same mutation that caused cancer in your neighbour
Choose DNA sequencing if you wish to ascertain if you are predisposed to cancer – you may carry new or rare variants in the disease-causing gene (such as BRCA1 or BRCA2), variants which are infrequent or have not been observed before, so genotyping will miss it, giving you a false sense of security
DNA sequencing is a more thorough procedure as it may uncover lesser known genetic diseases.
2. Price of Examination
Although price is an influencing factor when choosing a provider, don’t think that a higher price always means extra value. Instead, base your decision on the benefits the test offers compared to other tests.
Why does pricing fluctuate so much between types of genetic tests?
The price tag depends on the type of technology applied to the test. For instance, DNA sequencing is priced higher as there is more work involved in the analysis. One of the providers, 23andme charges $99 for their BRCA1&2 mutation test (SNP genotyping of 3 mutations), while Myriad Genetics charges $3400 for sequencing the same genes, though some third party labs can do it for $1000; it all depends on the provider.
Many labs have CLIA (Clinical Laboratory Improvement Amendments) and/or CAP (College of American Pathologists) certifications. These certifications do not assess a test’s utility and clinical validity. Instead, these certifications apply to laboratory practices, ensuring that your samples are handled correctly and results are reproducible. You cannot rely on a certification alone to base your decision. A certification ensures reproducibility of genetic data but doesn’t always ensure the clinical utility of genetic test. Before purchasing a genetic test, research the meanings of the genetic markers and technology that are being offered.
4. Number of Genes and Markers Tested
The majority of diseases are caused by several mutations in multiple genes, only rarely are diseases caused by mutations in a single gene. For example:
- Cystic fibrosis is caused by mutations in CFTR gene, but the gene may have one of 1900 known mutations
- Deafness can be caused by mutations in over 30 genes
- Risk of breast cancer is determined by more than 76 genes
When a higher number of genes are analyzed, the disease prediction is better but costs are higher. To make tests more affordable companies offer specific subsets of markers (panels) on a few genes for analysis of a particular disease – Breast and ovarian cancer, Cardiovascular panels, Alzheimer’s disease. It’s up to you to decide whether to analyze your entire genome at a higher cost or analyze only the necessary genes and spend less.
Which genetic test is best for me? What are my options?
There are a multitude of choices which come with a large variability in price. Comparing one product to another is tricky – disease risks estimates can relate poorly to one another because certain key genes may have been omitted from the analyses. The most common ones are:
- Specialized disease panel (“Slice and dice” approach) is cheaper, but less informative
- Heritable carrier status panel (3-300 genes)
- Drug response panel (one CYP gene at a time or entire set)
Use the DIY genomics application to compare how service providers combine different markers in various disease risk estimate.
5. Receiving your test results
There is a good chance that you will not fully understand all the implications of your test results, which may lead to unjustified anxiety (too much emphasis on the risk) or lack of action (not taking test results seriously). If you don’t understand your test results, it’s best to talk to a genetic counselor or a genetic consultant. Genetic counselors are certified professionals who are trained to interpret test results, while genetic consultants are PhD level scientists who specialize in genetic data analysis. These qualified individuals can have a meaningful discussion with you about the test results and answer your questions. Typically companies that offer consultations charge a premium for their services.
Typical questions to ask a genetic counselor or a genetic consultant
- Does the report clearly explain the options that one may employ to reduce the inherited disease risk?
- What about other family members – who may share the same risks?
- What happens if in the (near) future studies find additional markers for this disease?
Our knowledge about genes and their function is vast and is increasing rapidly. In the field of genetics, hundreds of peer reviewed publications are being published every month adding to the vast knowledge of genetic disease association that help us calculate estimates for disease risk. Our genomes are, more or less, fixed – our genes are what we have got from our parents, but our understanding of our genomes improves almost every day so disease risk estimates will change as more disease causing factors are annotated.
How can we help?
At Geneyouin we aim to provide you with various options for personalized testing. Our main goal is to analyze your personal genome, provide a lifetime value on your initial investment by sending you regular updates, and make the data useful every day though our mobile tools for personalized genome reference (coming out soon). Contact us for a free consultation at: 1-877-409-3629
If you would like to learn more about choosing a genetic testing, continue reading this related blog post: “Which Genetic Testing Technology Is Better?”.
Author: Ruslan Dorfman