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Clinical drug trial research brings hope for children who have rare tumor disease

Written By: Courtney Saenz | Updated: February 17, 2023
Sweet 2-year-old Nora is playing and excitedly talking with zero signs of developmental issues after being treated for tuberous sclerosis complex at UTHealth Houston. (Photo courtesy of Jennifer Stewart Photography)

Sweet 2-year-old Nora is playing and excitedly talking with zero signs of developmental issues after being treated for tuberous sclerosis complex at UTHealth Houston. (Photo courtesy of Jennifer Stewart Photography)

Cheryl Navar was 24 weeks into her pregnancy when doctors found multiple tumors in her unborn baby’s heart. Before baby Nora entered the world, her soon-to-be parents sat in their hometown in Corpus Christi to learn about a rare disease called tuberous sclerosis complex (TSC). 

Cheryl’s husband John did extensive research to find the best care for their child and quickly discovered the TSC Center of Excellence at UTHealth Houston. Nora was born on June 8, 2020, just months after the pandemic began. Through genetic analysis of a cheek swab, doctors confirmed the diagnosis.

“I am big researcher; I dove in headfirst and found out how debilitating TSC is. Learning about the hardships she would go through was rough for us. I knew finding the center and a study meant we were on the right track,” John Navar said.

TSC is a rare and neurologically impairing genetic disease. It is caused by a genetic change in either the TSC1 or TSC2 gene, which results in the dysfunction of a signaling pathway in the cell called the mammalian target of rapamycin (mTOR) pathway. The result is out-of-control growth of cells, resulting in benign tumors growing in multiple areas of the body including the brain, eyes, lungs, heart, kidneys, and skin.

The disease affects approximately 50,000 people in the U.S. Due to the location of the tumors, some people with TSC can develop life-altering symptoms. Children with the disorder have a 90% chance of experiencing seizures and a 50% chance of developing autism or a developmental disability that affects learning and speech.

The Navars traveled to meet with Hope Northrup, MD, geneticist and director of the TSC Center of Excellence, who referred them to the STOP-2 clinical trial at Cincinnati Children’s Hospital, a pilot study involving a drug called sirolimus, an mTOR inhibitor being assessed as a medication to prevent or delay seizure onset in TSC patients.

“Seizures are like a fire in your brain. Once they start going, they are hard to stop,” said Northrup, professor of pediatrics and Memorial Hermann Chair with McGovern Medical School at UTHealth Houston. “TSC is the perfect example for how we hope the story will be for all genetic diseases. We figured out which genes did not work resulting in the disease, then found a therapeutic intervention. We can help so much more now than we could in the past.”

Her parents enrolled Nora when she was 4 months old and between visits to Cincinnati, the family met virtually with Mary Kay Koenig, MD, pediatric neurologist, co-director of the center, and Endowed Chair of Mitochondrial Medicine, to monitor any seizure activity and development. At age 10 months, Nora had her first seizure and Koenig added an anti-seizure medication, which ended the seizures after about a week.

“When the seizures started, I was able to call Dr. Koenig at 7 p.m. on a Friday and she was responsive the entire weekend. I never felt deserted by the team,” Cheryl Navar said.

Nora’s enrollment in the STOP-2 trial ended when she reached her first birthday, after which her doctors prescribed sirolimus clinically. Using the experimental drug, along with the anti-seizure medication, and close individualized care given by the TSC Center, Nora has not experienced any more seizures. After being slowly being weaned off the therapeutic dose of anti-seizure medication, recent electroencephalogram (EEG) scans have shown no seizure activity.

Now 2 years old, she’s playing and excitedly talking with zero signs of developmental issues.

“This is all we wished for,” John said. “Now Nora will be able to live a fairly normal life.”

With the positive outcome of STOP-2, a subsequent study, Sirolimus TSC Epilepsy Prevention Study (TSC STEPS), is now underway at sites across the country, including UTHealth Houston.

For more information about the TSC STEPS trial, visit

To get in touch with the TSC Center of Excellence at UTHealth Houston, please contact Claire Sartwell at [email protected] or call 713-500-7149.

For media Inquiries: 713-500-3030

As the clinical practice of McGovern Medical School at UTHealth Houston, UT Physicians has locations across the Greater Houston area to serve the community. To schedule an appointment, call 888-4UT-DOCS.