3 Ways Genetic Knowledge is Power

The goal is prepared patients, not “patients in waiting”

DNA as a puzzle

“Patients in waiting.” It’s a term we in the world of genetics hear from time to time.

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The idea is that for certain conditions where there is no cure — or where it may be years before a patient shows symptoms — genetic testing can cause anxiety without providing steps for care.

I don’t believe that. What I do believe is that knowledge is power — when it is delivered in the right way. We want to empower patients as “previvors,” people with a predisposition for a disease and the power to do something about it. That’s why we rely so heavily on genetic counselors.

When a patient comes to us, a genetic counselor walks that patient through what a positive test would mean before any blood is drawn. In fact, part of the counseling process is allowing a patient to make an informed decision about whether he or she wants to proceed with testing.

I can tell you that fewer than 1 percent of our patients choose “not to know.” With the proper counseling, patients understand that for most conditions, knowing your risk can lead to better preparation, better prevention and — when available — better treatment.

Here are just a few examples.

1. Cystic Fibrosis

“We want to empower patients as ‘previvors,’ people with a predisposition for a disease and the power to do something about it. That’s why we rely so heavily on genetic counselors.”

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Charis Eng, MD, PhD

Founding Chairwoman of the Genomic Medicine Institute

The path of cystic fibrosis is broad and variable. In some cases, even if you have a genetic mutation, symptoms may take years to develop. The disease is a fairly classic example people point to when they say “patients in waiting.” However, knowing that you have a genetic mutation can still guide your care — as well as your planning.

What you can do if you have a mutation:

  • Monitor symptoms. Knowing you have the potential to develop cystic fibrosis can help you be prepared to treat symptoms if and when they arise.
  • Seek treatment from an appropriate care center when needed. Because of the partnership of advocacy groups with academic medical centers devoted to the disease, standards of care and life expectancy have improved greatly.
  • Use genetic information for family planning. Cystic fibrosis requires two mutations — one from the mother and one from the father. Knowing your own carrier status and your partner’s can help you make decisions such as whether to have children.
  • Be on the lookout for new treatments. For example, a new oral medication, Kalydeco™, was approved by the FDA in 2012. It’s the first drug designed to treat the faulty gene and protein defects responsible for cystic fibrosis.

2. Lynch Syndrome

Lynch Syndrome is the most common cause of genetic colorectal cancer. Unlike forms that appear later in life, the cancer risk with Lynch Syndrome begins as early as age 25. We search for mutations in three major genes — MLH1, MSH2 and MSH6 — in the setting of genetic counseling.

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What you can do if you have a mutation:

  • Start colon cancer screenings at age 25. Women in their 30s and 40s also should have regular biopsies of the endometrium because of other cancer risks, then regular ultrasounds after menopause. It’s truly a lifelong screening plan.
  • Knowing you have a Lynch mutation guides your surgeon. You may have years to decide, but a surgeon may recommend removing your entire colon if a small colon cancer develops. At-risk women also may consider removal of the uterus and ovaries to prevent other forms of cancer.
  • Have your family screened, too. Studies show that if we identify one person with Lynch syndrome, an average of two and a half family members also will have it.

3. Medullary Thyroid Cancer (MTC)

This is a rare but very serious form of thyroid cancer. Germline (heritable) mutations in the RET gene predispose people to MTC.  All individuals who develop MTC should be tested for mutations in the RET gene in the setting of genetic counseling. If there’s a family history of mutations in the RET gene, a person should automatically be tested for it, too.

What you can do if you have a mutation:

  • RET gene mutations are so specific they tell us exactly what to do. When a RET gene mutation is found, prophylactic thyroidectomy (removal of the thyroid) is offered.
  • After a life-saving thyroidectomy — which is done before MTC even develops — patients with a strong mutation have regular screening of the adrenal glands and parathyroid issues. If the mutation is weak, we may only need to screen for thyroid cancer. But either way, regular screening can prevent recurrence and save lives.

These are three very different examples, but they all have a common thread: Knowing your risk — if you want to — can help you seek the right treatment, monitor and manage your condition, and better plan your life.

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Charis Eng, MD, PhD

Charis Eng, MD, PhD is founding chairwoman of the Genomic Medicine Institute and founding director of its Center for Personalized Genetic Healthcare. Dr. Eng is a global leader in cancer genetics and cancer genomic medicine.
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