Rare Gene Mutation Could Be Mistaken For Cerebral Palsy
ST. LOUIS — When only 100 people in the world share your child’s specific gene mutation, it is hard to find anyone who understands, including doctors.
Three dozen families came here from Argentina, Italy and all over the U.S. this month to help doctors understand the medical challenges caused by a mutation of the GNAO1 gene. Symptoms including seizures, uncontrolled movements and developmental delays typically start in the child’s first year.
The gene mutation, discovered in 2013, probably has been misdiagnosed as cerebral palsy or other disorders in many more children and adults who have not had complete DNA testing, said Dr. Amy Viehoever, assistant professor of neurology at Washington University, which hosted the first-ever GNAO1 clinic on a recent Thursday and Friday.
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Doctors and researchers at the clinic are trying to build a diagnostic and treatment guide for the rare disease. They plan to hold the clinic every year to track the children’s symptoms and provide a baseline for researchers to measure success or failure if a treatment becomes available.
“Unlike something like Alzheimer’s or stroke with thousands and thousands of patients, in rare diseases we can’t do these big clinical trials with placebo-controlled studies,” Viehoever said. “There are a limited number of patients, and obviously these families are desperate for treatments.”
It’s thought that the GNAO1 mutation happens spontaneously and is not passed down from the parents. For now, the disease is so rare and new that it doesn’t have a name.
“Unless you’ve been in this situation, you don’t really get it,” said Tori Morgan of Lenexa, Kan., whose daughter Harlie, 7, was diagnosed in 2016. “Every doctor that we see, we are the ones explaining the diagnosis. We have to be the experts.”
Morgan said it was heartening to see Harlie and Ben Kuhn, 2, of Georgia, react to sunlight and a breeze with the same squinted eyes and excited grins when they first met outside the hospital.
The children, who do not walk or speak, were evaluated at St. Louis Children’s Hospital by occupational and physical therapists as well as Viehoever to gauge their fine and gross motor skills and social development. The therapy sessions were filmed for the researchers to study.
“Anything we can do to advance medical research is going to be better for Harlie and anyone else with the diagnosis,” Morgan said. “Hopefully it will get us closer to some actionable treatment.”
While there is no specific treatment or cure, some of the children take anti-seizure medications. Others have had deep brain stimulation, a surgery that is also used in epilepsy and Parkinson’s disease to control seizures and tremors.
The treatments usually help manage the symptoms, but a few children have died when severe muscle contractions affected their breathing.
“The first patients that have been described are pretty severely affected, which is not surprising because kids who are more sick are more likely to have lots and lots of tests to figure out what’s going on,” said Viehoever, who was one of the first doctors to recognize the disorder in a patient. There probably are milder forms of the disorder that have gone undiagnosed, she added.
Stephen and Emily Bell of Washington, and Duke and Alice Fox of Virginia, launched the nonprofit Bow Foundation to promote research and awareness after their children were diagnosed with the disorder. The foundation awarded a $65,000 grant to Washington University to help with the costs of the three-day conference.
Madeleine Bell is 4 years old but has the developmental ability of a 3-month-old, her father said. She averages four seizures a day even on medication and uses a feeding tube. Their foundation was named for her signature hair bows.
“She’s not able to communicate with us, but she’s a happy little angel,” Stephen Bell said.
While at the clinic, Bell got an email from a family in New Hampshire whose son was diagnosed that very week. With so little information about the gene mutation, doctors can’t offer a prognosis or life expectancy for the children.
“Because we don’t know, we focus on the days that we have,” Bell said.
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