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Double-Edged Helix

FIFTY-FIFTY. Susannah Gilbert was well aware of her odds, but in the cramped counseling room at UW-Madison’s Paul Carbone Comprehensive Cancer Center, she heard her genetic counselor go over them once more. It was a flip of a coin, a 50 percent chance that she had inherited her mother’s Lynch Syndrome, the genetic disorder that had caused her repeated battles with cancer. Although she was only 16 years old—active, healthy and hardly of the age to worry about cancer—Susannah knew that her own DNA was keeping a secret from her. And she was ready to know the answer.

If you had a genetic disease that might not emerge for years, if ever, would you want to know?

With her parents by her side around the Formica-topped table, Susannah nodded in quiet understanding. The Gilberts had been through this before. A few months earlier, Susannah’s older sister, Emily, had been tested for the disorder, and the whole family rejoiced when they discovered she didn’t have it. But privately, Susannah worried. “It felt like one of us should end up with it,” she confessed later. “I felt like I had a higher chance of having it somehow because she didn’t.” Now, it was her turn to learn the truth—information that would set her down one of two paths. Down one lay rigorous annual cancer screenings and the likelihood of surgeries, radiation and chemotherapy. The other path held the deceptively simple promise of a normal life.

For nearly two hours, Amy Stettner, who counsels patients through genetic testing for the UW-Madison-affiliated Waisman Center, walked Susannah through the steps that she would take to find out which path her life might follow. First, Susannah would provide a sample of her blood, which would be packed in a small tube and shipped to a lab in Salt Lake City, Utah. There, lab technicians would perform PCR amplification on the sample to hone in on a key part of her DNA. They would look for the presence of a small error in her genetic code in a process akin to checking to see if a book has a particular typo on a particular page. Once their testing was done, they would check one of two boxes on a form, either “No Mutation Detected” or “Positive for Deleterious Mutation.”

Then, two weeks later, Susannah would return to the small counseling room to learn the results. Either way, the test would reveal a deeply intimate piece of information about her, a glimpse into the very makeup of her being. On that day, she would discover information that, once known, could never be unknown. For better or worse, she would learn what her body might have in store for her future.

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SARAH GILBERT WAS 31 YEARS OLD when she got her first cancer diagnosis. She had been sick for more than a year, and she was shocked to learn she had been suffering from colon cancer. But then, after surgery to remove the tumor, it was gone. Three years later, Sarah was given a clean bill of health. She and husband Peter, who had just finished a master’s degree in library science at UW-Madison, decided to celebrate by having a second child. “Susannah was sort of our victory baby,” says Sarah.

A few years later, Sarah started having unusual menstrual periods. By then, the family was living in Appleton, Wis., where Peter had taken a job in Lawrence University’s library system. Thinking she was experiencing early menopause, Sarah tried alternative medicine. But doctors discovered something else: her second and possibly third cancers. “They couldn’t exactly tell from the pathology whether I had stage three uterine cancer that had spread to my ovary, or stage two uterine cancer and stage one ovarian cancer cropping up at the same time,” says Sarah. To be safe, Sarah was treated for both. She had a complete hysterectomy, followed by radiation therapy for her uterine cancer and chemotherapy for her ovarian cancer.

By this point, Sarah and her family were convinced that this was more than a string of bad luck. Sarah’s sister, a doctor living in Indianapolis, had recently read about Lynch Syndrome, which seemed to explain Sarah’s litany of cancers. Caused by a mutation in a gene that helps ensure DNA gets coded correctly when cells grow and divide, Lynch Syndrome carries a significantly elevated risk of developing tumors, especially in the colon (see box, page 32). While most people have a 2 percent chance of developing colorectal cancer during their lifetime, for instance, people with Lynch Syndrome face an 80 percent likelihood. Their odds of a second colorectal cancer within 15 years are 50-50.

But before Sarah had a chance to be tested for Lynch Syndrome, she was again diagnosed with cancer. This time, surgeons removed most of her colon, followed by three months of chemotherapy that were made tortuous by blood clots and infections. All this before she turned 44.

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