Only known person in SC with rare condition turns 3 as family raises awareness

As Savannah Amerson gets ready to celebrate her third birthday on Aug. 28, her mom is sharing her story to raise awareness about the little girl’s rare disorder. It’s called CTNNB1 Syndrome. It causes symptoms ranging from developmental delays to vision problems to issues with muscle tone.

“We want to get as many people as we can to just see the name of it and know that it requires genetic testing,” Emily Amerson said.

Genetic testing is how doctors determine whether a child has the condition. That’s important, because as Amerson has learned, rare disorders such as CTNNB1 Syndrome are sometimes mistaken for something else. And without the right diagnosis, understanding a child’s symptoms and getting the right care becomes more difficult. 

It started with concerns about head size

When Savannah was born, her parents had no idea that she had a syndrome that had just been discovered in 2012. “Her only symptom was a smaller head circumference. She behaved pretty normally the first three-ish months and then started missing milestones from there,” Amerson said.

The Amersons, who live in Huger, South Carolina, turned to MUSC Children’s Health in Charleston for answers. That’s where they met Neena Champaigne, M.D., the geneticist who diagnosed Savannah. Champaigne, who works closely with Greenwood Genetics as well, described how her team did it.

“There are probably hundreds of genes that can cause neurodevelopmental disorders. And so we use a technology called whole exome sequencing. We basically are able to sequence all 22,000 genes,” Champaigne said.

Ending the diagnostic odyssey

That sequencing, combined with the doctor’s knowledge of  Savannah’s symptoms, pointed to mutations in Savannah’s CTNNB1 gene. The gene plays a key role in growth and development, including in the brain. 

 

So the geneticist had her answer. It was time to share the news with the Amersons. Savannah’s mother remembers the moment well. “She was 10 months old. It was June of 2022,” Amerson said.

“I will never forget the wave of weakness that overtook my body as I opened the results on my phone. The top half of my body melted onto our kitchen counter as I read the words ‘positive’ and ‘neurodevelopmental disorder’ on the report.”

The diagnosis sent the Amersons on a quest to connect with other families whose children have CTNNB1 Syndrome – and get their daughter the best possible care. 

Meanwhile, Savannah’s team of doctors at MUSC Children’s Health continued a quest of their own, working together to care for the only child in the state known to have CTNNB1 Syndrome. 

Understanding the syndrome

CTNNB1 Syndrome can cause a series of developmental delays and intellectual disabilities. Symptoms include behavioral challenges, trouble sleeping, eye problems, low muscle tone and involuntary muscle contractions.

Savannah’s parents connected with other families online to talk about what their children are dealing with, tell their stories and advocate for new treatments and a cure. 

 

“I would say the community aspect has been the most powerful part of the diagnosis,” Emily Amerson said. “We're learning things medically about the population, like tethered cord. We might never have known to ask about tethered cord had it not been a bunch of parents posting about it in this Facebook group.”

A tethered spinal cord is associated with CTNNB1. Neurosurgeon Ramin Eskandari, M.D., explained what it is. “The bottom of your spinal cord, during development, has a little connective tissue that goes from the very bottom of the spinal cord all the way down to your tailbone. It’s important during fetal development,” he explained.

“But every now and then that connective tissue piece is too tight. The cells in it aren't correct. There's fat infiltrated in it, or it’s just a congenitally tight thing. And then, as you're trying to grow and stretch, it's holding on too tightly.”

It can cause major problems if left untreated. Eskandari made sure Savannah got the care she needed. “If you have it, the treatment is not super hard. You actually just kind of go and usually cut that little connective tissue piece that is holding everything too tightly,” he said.

He makes it sound easy, but his team takes great care with the children they treat. “We use magnetic resonance imaging to verify the level of the spine we need to operate on. That removes the need for radiation-based imaging for these patients,” Eskandari said. 

“We also use neurological monitoring in the surgery, making sure all nerves are monitored so we can be as safe as possible when you're cutting something that's near the spinal cord.”

A tethered spinal cord isn’t the only concern to watch for as children with CTNNB1 Syndrome grow. The condition can also cause heart problems, affect bone density and cause scoliosis, among other concerns, according to the patient advocacy group CTNNB1 Connect and Cure. Amerson recently became president of that organization. 

Savannah and her family today

Savannah heads into her third year of life with strong family support and love. “She's growing like a weed,” her mother said.

 

“She's worn glasses since she was 7 months old. And she is working on walking, and she is working on learning how to use an augmentative and alternative communication device. It’s a tablet where she can press buttons on the screen, and it'll talk for her. She's nonverbal, but she understands what we're saying. So we're working on trying to get her to express herself, if not with spoken words, at least with the device.”

Her parents stay busy. Savannah now has a sister,10-month-old Nora. And the Amersons take Savannah to appointments each week. “She does eight sessions of therapy every single week for speech, physical and occupational therapy,” Emily Amerson said.

They’re also participating in research involving CTNNB1. Amerson said several different treatment approaches are in development for the syndrome, including small-molecule drugs and gene therapy. There are ongoing natural history studies of people with CTNNB1 Syndrome to understand more fully the natural progression of the disease and to prepare for clinical trials. 

Amerson said CTNNB1 Syndrome isn’t easy for the people who have it or their loved ones. “I feel like not a lot of rare disease families are vocal about the burden it can cause on the entire family. We love her to pieces, and we celebrate all of her milestones, but her not being able to communicate causes a lot of intense frustration.”

And since Savannah can’t walk yet, her parents carry her up and down stairs. They also feed her since she can’t feed herself.

 

"I would love for her to be able to tell us, whether it's with the device or verbally, one day, what she's thinking, what she did that day, what she needs. I would love for her to be able to move around on her own. Obviously, I'd love for her to be able to walk. But if not that, maybe a wheelchair or walker. So more independence and communication is what we hope and pray for her to be able to have one day.”

Amerson said the syndrome seems to hit each child a little differently, so it’s unclear what lies ahead for Savannah. But taking an active role in Savannah’s care, whether it’s through therapy appointments, medical discussions or online advocacy, is an important part of her life. “I feel like I'm actually making a difference. And that's been huge.”