How do genes affect your health?

How do genes affect your health?

It was a post on Facebook that caught Angela’s attention*. The 36-year-old has thought about her genetic testing for years, ever since her sister was diagnosed with breast cancer and tested positive for the BRCA1 gene mutation more than a decade before her.

His sister had encouraged the family to get tested: the BRCA1 and BRCA2 mutations can significantly increase the risk of breast and ovarian cancer, but Angela didn’t feel ready. She was already dealing with anxiety and obsessive compulsive disorder (OCD) and she wondered how she would feel about the results or whether having the gene would affect her decision to have children.

Then, last summer, the now mom of two saw a friend’s Facebook posta home genetic testing program that offers a test that checks for more than 60 genetic markers for cancer, including BRCA. Doing it at home — you basically use their “spit kit” and mailing your own sample — was less intimidating for Angela than going in person, so she decided to give it a try.

About three weeks later Angela got her results: she had the BRCA1 gene. Though devastated, talking to her company’s genetic counselor about her options helped her feel less overwhelmed. After talking to a gynecological surgeon, she decided to have a total hysterectomy (removal of the uterus and ovaries) to reduce the risk of uterine and ovarian cancer. Before that though, another doctor on her care team wanted her to have a mammogram and a breast ultrasound, both of which came out clear.

But due to her genetic predisposition, her doctor went one step further: an MRI scan. It was then that they discovered a small mass, which a biopsy later revealed to be stage 1 breast cancer.

Within a few months, Angela had the recommended hysterectomy and a double mastectomy. Now cancer free, she will start taking medication tamoxifen to reduce the risk of cancer recurrence.

“They saved my life,” said Angela of the genetic testing company. Without it, she doesn’t know how long it would have been before her cancer was discovered. “Because I had this gene, (the doctors then) gave me MRIs,” she said. “She gave them the fuel to go the extra mile, to be more diligent and that’s when they discovered (cancer).”

How do your genes affect your health?

“There are changes in your DNA sequence, or in your genes, that make you more likely to develop a particular condition,” he explained. Elizabeth Jordan, MS, LGC, a licensed genetic counselor and associate professor of internal medicine at the Ohio State University College of Medicine. When this happens, it is called a genetic predisposition.

Experts have identified many genetic conditions — from cystic fibrosis to sickle cell disease to cancer. For example, some of these are caused by a single gene while others are multiple gene mutations that together increase your risk, Jordan said.

What genetic conditions should you know about?

Jordan points to three in particular to put on the radar: familial hypercholesterolaemia (the official term for genetic high cholesterol), hereditary breast and ovarian cancer (HBOC), and hereditary non-polyposis colorectal cancercalled Lynch syndrome.

The Centers for Disease Control and Prevention (CDC) lists them in a First level category which means there is evidence that understanding risk and taking action can be beneficial. “Basically these are conditions that are very common in the general population and that not just women, but everyone should be aware of,” Jordan said.

Let’s take a closer look:

Genetic high cholesterol: About 1 in 250 people have this common condition. “If your LDL, or bad cholesterol, is around 190 milligrams per deciliter, it usually raises a red flag out of concern that this is really more driven by genes rather than poor eating habits,” Jordan said.

Hereditary breast and ovarian cancer: 5 to 10 out of 100 cases of breast cancer are hereditary and 10 to 15 cases of ovarian cancer are hereditary. The most common genes associated with these hereditary cancers are BRCA1 and BRCA2. Having a gene mutation doesn’t mean you’ll definitely get breast cancer, but women with a BRCA1 or BRCA2 gene mutation are more likely to develop breast cancer by age 80 than the average woman.

Lynch syndrome: This genetic condition can increase the likelihood of developing colorectal cancer and many other cancers, including cancers of the endometrium, stomach and uterus. Lynch syndrome is estimated to be the cause of 3-5 percent of colorectal cancer cases and 2-3 percent of endometrial cancer, according to the American Society of Clinical Oncology.

With all of these diseases, some symptoms, family history, and age of diagnosis — for example, if you’re under 45 and diagnosed with breast cancer — can tell doctors (and you) whether genetics might be at stake.

Knowing this information can be helpful both for preventative measures, such as how Angela had a hysterectomy, and for treatment options. For example, if you know you have a family history of high cholesterol, ask your doctor about medications tailored to your condition. “I’m excited to finally be in an era where we have cholesterol management drugs designed specifically for people with genetic high cholesterol,” said Jordan.

What about mental health conditions?

Research suggests that some mental health conditions can also have a genetic component. For example, inside a 2022 study published in the journal Nature, the researchers were able to point to a number of genes that may be associated with schizophrenia.

Conditions like schizophrenia, depression, anxiety and bipolar disorder are considered complex, Jordan said, meaning both genes and environmental factors tend to be at play for the people who develop them. While some genetic testing exists, a genetic counselor can look at things like family history, age at which symptoms start, and evaluation options to determine if it’s helpful.

Understanding genetic testing

Depending on your circumstances, such as if there are warning signs in your family history, such as your mother and grandmother had ovarian cancer, your doctor may recommend genetic testing. (Prenatal genetic counseling and testing is also an option for expectant parents.)

First, a genetic counselor will perform a genetic risk assessment that looks at things like family history, which often goes back three generations, Jordan said. “If you meet the right criteria and if there are risk factors, genetic testing would be facilitated,” she said.

Testing — a blood or saliva test – usually happens after and in a clinical setting, although there are also home tests. Some of these at-home options are through a medically supervised clinical laboratory and genetic counselors available to interpret the results.

Others are what’s known as direct-to-consumer (DTC) genetic testing (think: 23andMe and AncestryDNA). These types of tests can’t offer as many details as clinical trials, but they can give you some background information and can offer interesting insights like whether you prefer chocolate or vanilla. While these at-home tests can be fun, they shouldn’t replace professional genetic counseling if a genetic condition is suspected.

But no matter what type of test you have, talking to a genetic counselor about your results is crucial, even if you test negative for genetic markers. Sometimes, your family history alone is enough to recommend ongoing monitoring.

There are also online tools including the OSU Family Health Calculatorwhich calculates the risk for various genetic conditions based on family history.

And this can be a good way to start. “The goal (with the calculator) is for you to have something that you can print or download and show your doctor to start the conversation,” Jordan said.

Working with genetic test results

Here’s the thing with genetic testing: It’s important to remember that the results can have a real impact on your life.

“There are some people who haven’t arrived yet,” Jordan said. “They don’t feel empowered by having this information, but they might feel a little more fatalistic about it.” And that’s not always a healthy approach. “If it’s going to reduce the preventative action you could take, then maybe it’s not the most appropriate thing,” she said.

if you I am ready and the results show that you have a certain genetic predisposition, there are positives, namely the possible treatment and prevention courses that you may be able to take.

And while we have no control over the genes we inherit, there are some things we can control including diet, exercise, making healthy choices, quitting smoking, and preventative care like cholesterol checks, mammograms, and colonoscopies.

“These are all things within our control that we can use to change what our genetic predisposition makes us more prone to develop,” Jordan said. “My perspective has always been, knowledge is power.”

*Name used for privacy only

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