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Healthy You

Genetic Testing Advancements Drive Precision Medicine

Tuesday, March 06, 2018 7:51 AM

Aggressive Stage 3 breast cancer struck Jenny McCarthy in the prime of her life. Only 36 years old and mother to three young daughters, she was completely shocked by her diagnosis. McCarthy, now a resident of Elk Grove Village, was a self-described “fitness junkie” who had been raised by a nutritionist and had no family history of cancer.


Given her age and the severity of her disease, McCarthy’s physicians immediately suspected that a genetic component was likely. In 2004 she was tested for mutations in the well-known BRCA1 and BRCA2 genes that are linked to an increased risk for breast cancer, but the results came back negative.

Mysterious New Symptoms
McCarthy underwent a bilateral mastectomy and chemotherapy, continuing to work at a demanding corporate job throughout her grueling treatment. She beat the cancer, but then began to develop an array of seemingly unrelated health issues including autoimmune disorders, an irregular heartbeat and muscle weakness and numbness.

“Some of the strangest things were happening to me,” recalled McCarthy. “Nobody knew where all of this was coming from. The doctors just kept telling me that my body had been through a lot fighting the cancer.”

Her condition worsened to the point that McCarthy was forced to quit her job and go on disability in 2009. “There was a long period of time when I was really sick. I managed one day at a time, taking care of my kids,” she said. “The whole time I felt there had to be something that tied all of these problems together.”

Search for Answers
Frustrated by multiple hospitalizations and no significant improvement in her symptoms, McCarthy decided to switch her healthcare team to NorthShore. She also began exploring the idea of new genetic testing and began working with Peter Hulick, MD, Medical Director of NorthShore’s Center for Personalized Medicine. She was tested again last year, this time with a whole panel test that looked at breast cancer genes beyond BRCA1 and BRCA2. This type of advanced DNA testing was not even available when she was diagnosed in 2004.

“The field of medical genetics and personalized medicine is rapidly evolving, and Jenny’s case is a classic example of how the knowledge and expertise we have today is providing new and potentially life-changing information,” explained Dr. Hulick, who holds an academic appointment at the University of Chicago Pritzker School of Medicine.

Critical Discovery
McCarthy’s DNA test revealed two genetic mutations, one on each copy of her ataxia-telangiectasia mutated—or ATM—gene. This combination typically causes a rare condition that is associated with increased cancer risk and neurological complications. While the ATM gene helps regulate cell growth and protects against DNA damage, McCarthy’s mutations prevent her genes from functioning properly, confirming a genetic link to very serious—even potentially fatal—neurological condition.

“At first I didn’t really know how to get my head around this new information. It was almost too much,” noted McCarthy. “But truly, it’s been good to finally get some answers. I’m always looking for ways to get better and this is actionable knowledge.”

Jenny Cat

Proactive Care Management
With Dr. Hulick’s expert guidance, McCarthy now sees specialists who regularly monitor her health and her newfound genetic risk of disease. Kellogg Cancer Center Medical Oncologist Elaine Wade, MD, keeps watch on any potential cancer recurrence, and NorthShore Neurological Institute Neurologist Ashvini Premkumar, MD, who McCarthy credits with helping to unravel and treat her neurological issues, keep McCarthy strong.

“It’s phenomenal to have this genetic finding that sheds new light on Jenny’s condition. I wouldn’t have been able to diagnose her without this information,” said Dr. Premkumar. “She’s incredibly resilient and dedicated to her wellness.” Drs. Premkumar and Wade also hold academic appointments at the University of Chicago Pritzker School of Medicine.

“I feel better than I’ve felt in a long time,” added McCarthy, who also takes steps to keep herself healthy, including healthy eating, drinking plenty of water, getting enough sleep and practicing yoga to help with pain management and joint issues.

Family Matters
McCarthy said her three daughters were a major impetus for her to undergo the new genetic testing. Based on the discovery of her rare ATM mutation, she wanted them to be aware of their own genetic risk. “Dr. Hulick has been great,” she said. “He even worked with my older daughter who is out of state, and connected her with medical genetics professionals.”

All three younger women will work with their physicians to undergo appropriate screenings due to their elevated risk for breast cancer. When they decide to have children, they also will go through genetic counseling and have their partners tested to rule out ATM.

“This is a journey for a lot of patients, and for Jenny, the journey has been long and winding,” emphasized Dr. Hulick. “When it comes to genetics, we’re uncovering more and more tools every day to help improve patient care.”

“When I transferred my care to NorthShore, they got me back on my feet,” added McCarthy. “The quality of care is excellent, and I believe my doctors really care about me.”