Learning about Genetic Testing
- Seth Rogan, 40, and his 41-year-old wife Lauren Miller Rogen have revealed how they are coping with his mother-in-law’s diagnosis of genetic early-onset Alzheimer’s disease at 55 years old.
- The Mayo Clinic says “having at least one APOE e4 gene increases your risk of developing Alzheimer’s disease two- to threefold.” But having two APOE e4 genes makes your risk even higher – “approximately eight- to twelvefold.”
- Not all genetic testing for disease is actionable in a specific way to prevent disease, other than lifestyle modification.
- For cancer, there are some findings from genetic tests which are actionable. Genetic testing indeed help predict an individual’s cancer risk by looking at inherited gene mutations. These results can provide potentially life-saving information for patients who test positive for known mutations and who then can undergo preventative screenings, preventative surgeries or even specific treatments for cancer if they’ve already been diagnosed.
Seth and Lauren, who co-founded the national nonprofit Hilarity for Charity with some friends back in 2012, spoke with PEOPLE this week to reveal that comedy is “absolutely part ” of how they cope following an Alzheimer’s diagnosis.Read More
Now, Lauren is urging others “to know yourself, know your numbers, know your genetic risk factors” and “don’t be afraid.”
“Because there are things that you can do to modify your genetics and to make lifestyle changes and live a brain-healthy life and potentially either delay or even maybe even prevent dementia or Alzheimer’s,” she explained.
Seth noted that he, Lauren, and the rest of their charity aims to give caregivers of those with Alzheimer’s “an easier load to bear” though financial and emergency planning resources.
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All About Alzheimer’s
Alzheimer’s, described by the National Institute on Aging as “a brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to carry out the simplest tasks,” affects more than 6.5 million people across the U.S.
According to the Mayo Clinic, “a very small percentage of people who develop Alzheimer’s disease have the young-onset type. Signs and symptoms of this type usually appear between ages 30 and 60 years. This type of Alzheimer’s disease is very strongly linked to your genes.”
“Scientists have identified three genes in which mutations cause early-onset Alzheimer’s disease,” the clinic explains. “If you inherit one of these mutated genes from either parent, you will probably have Alzheimer’s symptoms before age 65. The genes involved are: Amyloid precursor protein (APP), Presenilin 1 (PSEN1), and Presenilin 2 (PSEN2).”
Meanwhile, 15 to 25 percent of the general population carries an APOE e4 allele. The gene APOE e4 is a gene that increases the risk of Alzheimer’s and is associated with getting the disease at an earlier age.
The Mayo Clinic explains that “having at least one APOE e4 gene increases your risk of developing Alzheimer’s disease two- to threefold.” But having two APOE e4 genes makes your risk even higher – “approximately eight- to twelvefold.”
Understanding Genetic Testing
Genetic testing can provide people with greater knowledge to work with when considering their risk for certain diseases like Alzheimer’s. And it can also do the same for cancer.
Related: Actor Chris Hemsworth Has 8X Greater Chance of Getting Alzheimer’s
With breast cancer, for example, gene mutations of the PALB2, BRCA1, BRCA2, ATM, TP53, CHEK2, PTEN, CDH1 and STK11 genes can lead to inherited breast cancer.
Should I Get Genetic Testing to Assess My Risk for Breast Cancer?
It’s important to note, however, that BRCA and PALB2 mutations are much more common and can increase a person’s risk of breast cancer more than the others mentioned. If a parent carries a BRCA gene mutation, there’s a 50-50 chance you could be carrying it too.
Dr. Julie Rani Nangia, an assistant professor at Baylor College of Medicine, previously told SurvivorNet about 10 percent of patients who undergo genetic testing will test positive for the BRCA1 or BRCA2 gene, but an additional 5 to 6 percent will test positive for other genes.
RELATED: Genetic Testing: What Is It and Why Is It Important? An Interview with Breast Cancer Previvor Erika Stallings
About 10 percent of breast cancers are hereditary, according to Dr. Ophira Ginsburg, the senior advisor for Clinical Research at the National Cancer Institute’s Center for Global Health. So, she recommends genetic testing usually only for women who have a family history of rare cancers, family members with breast or ovarian cancer and other cancers associated with the Lynch Syndrome (a genetic condition that puts you at high risk for certain cancers) or a family history of common cancers diagnosed at a young age.
Inherited Genetic Disorders in Colon Cancer: FAP
Other cancers like colon, pancreatic and ovarian cancer – which can have hard-to-spot symptoms – can sometimes be detected earlier with genetic testing. And this generally means better treatment outcomes.
Given that a patient with pancreatic cancer does not always have the best prognosis, Jessica Everett, a genetic counselor at NYU Langone’s Perlmutter Cancer Center, suggests people with a family history of the disease take action to assess their risk level.
“If you’re concerned about pancreatic cancer in your family, start by talking to a genetic counselor to learn more about your risk and what options you have,” Everett told SurvivorNet.
Genetic testing can be used for preventative measures, but it can also be very helpful in navigating treatment options after a cancer diagnosis. With ovarian cancer, for example, BRCA 1, BRCA 2, PALB2, ATM gene mutations can point doctors toward PARP inhibitors which work by preventing cancer cells from repairing their own damaged DNA.
Genetic Testing Can Help Guide Ovarian Cancer Treatment Decisions
“Certain individuals with ovarian cancer, if they proceed with genetic testing and they test positive in specific genes, they might benefit the most from having PARP inhibitor medicine prescribed for them as treatment for their ovarian cancer,” says Lauren Mills, a genetic counselor at UT Health San Antonio, adding that women who test negative for mutations in these specific genes may also benefit from PARP inhibitors.
How Genetic Testing Determines Treatment in Lung Cancer
And when it comes to lung cancer, genetic testing can reveal the presence of certain genetic mutations — including KRAS, ALK, EGFR and a number of others — which can help doctors tailor treatment for each person’s specific disease.
Overall, genetic testing can be a great way to better understand your risk of developing certain cancers as well as best potential treatment options if you’ve been diagnosed with a certain cancer. But people should be aware that direct-to-consumer genetic testing companies like 23andMe do not give you the in-depth genetic analysis needed to fully understand your cancer risk.
Buyer Beware: Direct-to-Consumer Genetic Testing
Dr. Ginsburg says the tests can identify BRCA1 and BRCA2 mutations in Ashkenazi Jews at a very superficial level, for instance, as they test only a fraction of the genes’ thousands of mutations. Dr. Ginsburg warns “buyer beware” because you could end up with a false sense of reassurance.
“For this reason, we really encourage people to seek proper genetic counseling from a certified genetic counselor, even if it’s a commercial laboratory that can provide such a service over the phone,” Dr. Ginsberg said, adding that insurance companies will likely cover the genetic tests done by a healthcare professional if you’re a high-risk profile for breast cancer.
Contributing: SurvivorNet Staff
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