Inherited Diseases and What Genetic Testing Can Uncover

With genetic testing, you can determine any risk you have of inheriting or contracting genetic diseases. Health conditions that may exist in your family or you've inherited from your parents can be detected early with DNA testing, empowering you to make better decisions for your health.

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Genetic testing can tell you the following:^1,2

• Potential inherited diseases (because of gene mutations that have been passed down)
• Carrier status for health conditions
• Ancestry information, such as where your ancestors may have originated from
• Potential relatives or long-lost family
• Pharmacogenetics, which is what medicine may be effective for you and your conditions based on your DNA
• Any conditions your baby might have inherited (called prenatal testing if you're pregnant)

Remember that genetic testing results aren't fully conclusive, so further confirmatory tests and interpretation from your healthcare provider are the best courses of action after you get your results.

You’ve likely heard someone say, “It’s genetic” or “It runs in the family” when referring to a particular health condition.

Most people know that you inherit certain diseases and health conditions and that family medical history always affects your health risk. However, many don't always understand what it means to be at risk for a genetic disorder.

Does DNA Testing Provide Risk Assessment?

Yes. DNA tests are geared towards analyzing your DNA for health purposes and can tell you more about what genetic conditions you may be at risk for.²

Not only do genetic tests offer insight into diseases like sickle cell disease, breast cancer, or even other types of cancer or illnesses that may get passed down in families, but some can also analyze what kinds of changes and medicine may work best for you. All of this information is based on your DNA sequences and what they reveal.

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However, note that DNA tests don't provide enough information to justify making important health decisions.

They do give you a starting point and something to discuss with your doctor or medical geneticist about risks you have based on genetics, so they can still give you a headstart. Some people even meet with a genetic counselor and genetic counseling to discuss their specific results.

Most kits help you assess your inherited risk for developing a disease, but they don’t consider all the other factors affecting your risk.

Does Every Risk a DNA Test Detects Guarantee Your Health Will Suffer?

No. Just because a DNA test says you may be at risk, it doesn't necessarily mean you're going to contract the condition and suffer.

Genetic diseases and DNA testing are more complicated than just taking a test and knowing which health risks you may face. Diagnostic testing to confirm what DNA tests may be required afterward for a full, even more comprehensive genetic diagnosis.

For example, a DNA test might show you have genetic markers that put you at risk of becoming an alcoholic. But if you abstain from drinking alcohol, you’ve significantly reduced that risk. The same is true for most health conditions, but your chances depend on your diet, lifestyle, and environment.

Your genetic risk is just one of many factors that play a role in whether or not something will occur. Some people call genetic testing predictive testing because it can help predict chances, but it's not totally conclusive.

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Understanding Your Risk of Inheriting a Disease Requires a Comprehensive Assessment

In order to best understand if you're at risk of inheriting a genetic disorder, you can take a DNA test—as long as you make sure you verify your results with a professional.

The best DNA tests can give you a comprehensive breakdown of what you might already have or what your parents have passed on to you.

You can always accomplish a DNA test at a clinic or DNA testing lab, or you can take an at-home DNA test. Either way, genetic testing provides insight into potential health risks.

But understanding how much of a concern a particular disease is for you requires a much more in-depth look so you can gauge if you need medical care and look into treatment options or not.

For example, some diseases with a genetic link require the inheritance of a particular gene from both parents. Having inherited just one gene from just your mother or father amounts to only a little risk, if any at all. This is why some inherited illnesses seem to skip a generation (like cystic fibrosis).

Why Do Some Diseases Skip Generations?

Some diseases "skip" generations for various reasons, the most common being that some diseases require two copies of the mutated gene to manifest, and you only inherited one.

This is called an autosomal recessive genetic disorder.³ So if you have a parent who has the gene for a specific condition, it doesn't mean you'll get it, too—especially if your other parent doesn't have it.

The opposite of this is called an autosomal dominant disorder, where just one copy of the mutated gene is enough for you to be affected.

So, in a way, many disorders are not necessarily skipping generations. They're present but not expressed. The people who have these mutated genes but aren't affected by them are called carriers. Carrier screening tests can help you better understand your status.

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Other reasons diseases may skip generations (or seem to skip generations):⁴

• Other gene mutations may be affecting how much another gene variant is expressed.
• Reduced or incomplete penetrance, meaning that the gene itself doesn't have the same effectiveness or strength as it does in previous generations.
• The gene expresses itself in a variety of ways, making someone who may have inherited a mutated gene not necessarily look or seem like they have the condition the mutation is connected to. This is because they're expressing a symptom that isn't as commonly observed or associated with a disorder.
• X-linked disorders are disorders that are passed down via the X chromosome. Because biological women have two X chromosomes, they can usually manage because even if one X chromosome carries a disorder, they have the other to lean on. Biological men, however, only inherit one X chromosome, so they may contract a condition their mother was carrying.

Beyond these reasons, environment, lifestyle, and the way a child is raised also affect their chances of contracting a disease.

They may inherit the risk, but if they can manage their health well and are taken care of, there's a chance they may still live their lives without ever being affected, despite family history.

Genetic testing and prenatal testing can let you know more about carrier status, if you and your partner may have the same mutated gene, or if your baby will also inherit it.

Will Carriers Always Pass Diseases to Their Offspring?

No. Carriers won't always pass diseases on because they may require two copies of mutated genes, they may be linked to sex chromosomes, or the gene itself is just not "strong" enough to fully express itself or its more severe symptoms.

Genetic risk factors may just be that, risk, and not necessarily promised.

To get the best idea of whether or not you will pass on a disease to your offspring, you can consult a medical geneticist, request for a prenatal diagnosis, or undergo carrier screening.

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What Diseases Can DNA Testing Detect?

DNA testing can detect many diseases, such as:^5,6

• Cancer – Breast cancer, ovarian cancer, and other cancers can sometimes be passed down in families
• Mental health disorders – Bipolar disorder, depression, anxiety, and other mental health ailments can also run in families
• Cardiovascular disorders – Heart disease, hypertrophic cardiomyopathy, long QT syndrome, and familial hypercholesterolemia are just some of the mutations that can be passed down
• Neurological disorders – Diseases like Tay-Sachs, Alzheimer's, Parkison's, and even dyslexia can run in families
• Psoriasis
• Obesity and other metabolic disorders

What Else Can DNA Tests Tell Me?

DNA testing can also give you an idea of other complex traits, but some of these are more common with an interplay of factors beyond the genes you're inheriting.

For example, if there's a history of addiction in the family, it might mean that somewhere in your DNA sequence, you and your family members may:⁷

• Share similarities with your dopamine receptors in that you habitually search out "rewards" or instant gratification (substances are a good way to repeat that high)
• Have family members that fully have substance abuse disorder
• Have mutations that are vulnerable to addiction, like poor responses to withdrawal
• Share the likelihood of mental and physical illness, like chronic pain, suicidal ideation, heart disease, or bipolar disorder

Again, this may come about by a variety of factors working together, so it's not a guarantee.

Other things your DNA test can tell you are:

• Your potential eating habits
• Fitness advice based on your genes
• How you may respond to certain medications
• Your heritage, ethnicity, or ancestry
• Other traits that may not be immediately observable

Pros of DNA Testing

There are plenty of benefits to DNA testing, such as:

• Better insights into your own health
• A good understanding of your genetic risks and how you can curb them
• A look into your family, heritage, and ancestry
• More deliberate family planning since you have a better understanding of what you may or may not pass on to your children
• Use in forensics and identifying victims or suspects
• More tailored, personalized medical care and treatment
• Carrier screening and early detection
• A more complete idea of cultural identity

Cons of DNA Testing

DNA testing can also come with some downsides and challenges, such as:

• Anxiety around results (both when waiting and getting them)
• Emotional distress about potential risks
• Privacy concerns if DNA testing facility suffers security breaches
• Added cost of needing interpretation of data and confirmatory tests
• Potential inaccuracy
• Family tension or discomfort if you discover uncomfortable truths

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What Should I Consider Before a DNA Test?

There are several factors you should take into consideration before taking a DNA test, such as:

• What your goal is
• The validity of the clinical laboratory or DNA testing facility
• Accuracy of the test
• How secure your personal information will be
• If they can destroy your DNA data or sample afterward
• The emotional or psychological toll it may take on you or family
• The limitations of genetic testing, especially since it shouldn't be treated as totally conclusive
• If you have any medical counsel post-test that you can consult

What Should I Do Before and After a DNA Test?

Before a DNA Test

Before taking a DNA test, make sure you are emotionally and mentally prepared. Genetic testing may deliver some potentially devastating or shocking news, so make sure you're 100% certain about your decision and clear with your intentions.

Some tests may require different samples that may also require different preparation. Most DNA testing facilities or companies will instruct you accordingly so they can get an accurate sample and provide you with good results.

After a DNA Test

After a DNA test, wait for your results and try to be patient and level-headed. It can be anxiety-inducing, but panicking won't make them come any faster.

Once you have your results, do not jump to conclusions. Consult with your healthcare provider or a genetic expert to get a better understanding of what your results tell you. They can interpret your results much better and can even guide you to what you should do next.

If your results show you are at risk for anything, follow your doctor's orders. Whether it's getting confirmatory tests done or turning to medical treatment, they can provide you with the best course of action for you.

Can a DNA Test Tell Me If I’ll Get Cancer?

A DNA test kit will not outright diagnose you with cancer. It will tell you of your risk for it or if you inherited genes associated with it, but not if you will get it with certainty or if you already have it.

Taking a genetic test should not replace health screenings. The test cannot even provide your specific risk for cancer, even if you already have cancer.

What a DNA test can do is be the starting point for speaking to a genetic counselor. Doing so provides a more comprehensive look at your risk of getting cancer.

A DNA test can also tell you if you should consider healthy lifestyle changes because you might have an elevated risk.

If you need a push to finally start exercising or eating better, your test results might provide you with this. But they should not inform major health decisions and should never be a reason to worry yourself sick over your risk of developing cancer.

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Can a DNA Test Tell Me If My Kids Are At Risk For Anything?

A DNA test kit can help you evaluate your medical risks or understand what potential risks your children might face if you decide to conceive. However, remember you need a thorough medical screening with your doctor's input to get a complete picture of where you stand.

With prenatal testing or regular DNA testing done before conception, you can identify any mutated genes you may pass on. You or your partner may be carriers, so getting tests done can determine if your kids may face greater risk.

Can an At-Home DNA Test Tell Me the Same Things?

Yes, they can.

Many at-home DNA tests are pretty accurate and are even CLIA-approved, so you can trust DNA tests you can buy off shelves and online. Just make sure you do your due diligence and look up the best one for you, as different companies sometimes offer different features.

Tests done in labs aren't necessarily better, but some people trust them more to be careful with samples and carry the tests out in a more controlled environment. However, at-home tests are a great option, too, provided you follow the instructions and send your sample in properly.

DNA Kits Help You Screen for Risk

DNA tests are valuable tools to help you begin exploring your genetic health risks.

These tests are not intended to be diagnostic. Instead, they are a starting point.

Chances are you won’t be surprised by your results, but you can use them to learn more about your health and make changes that allow you to live your best life.