Mary Bridge Children’s Hospital provides gene therapy for children with neuromuscular disease

The blood test that day included a genetic screen, which revealed two important things: Weissenfluh was having a girl, and she was a carrier of a severe neuromuscular disease called spinal muscular atrophy (SMA). Shortly after, they learned that her partner, Alex, was also a carrier.

“They told us right then that there was a chance she’d have it,” Weissenfluh said, referring to her daughter, Braelynn. “Before then, we didn’t even know what SMA was.”

Shortly after Braelynn’s birth in November 2019, their fears were confirmed with her SMA diagnosis.

“When the doctors told us, I instantly just broke — I bawled my eyes out,” Weissenfluh remembered.

SMA is a degenerative neuromuscular illness caused by a missing gene, SMN1, and affects 1 in 10,000 babies in the United States each year. Amy Yuen, MD, a genomics physician at Mary Bridge Children’s Hospital who took on Braelynn’s case just weeks after her birth, explained, “In patients with SMA, the SMN1 gene is missing or not working. This means an important protein called SMN (survival motor neuron) doesn’t get made. SMN is critical, and without it, the motor neurons die, which makes the muscles weaker and weaker.”

Thankfully, 2019 was also the year that Mary Bridge Children’s opened its spinal muscular atrophy treatment program, and Braelynn was able to receive a drug called nusinersen (brand name Spinraza). It is injected into the spinal fluid and alters a similar, healthy gene to produce the missing SMN protein. With this therapy, Braelynn did not get weaker, rather she began to gain strength.

In May 2020, her bloodwork showed that she was eligible to get Zolgensma, a one-time gene therapy that helps the body to start making the missing protein on its own. “Zolgensma delivers a working copy of the missing gene. This lets the neurons make the SMN protein and allows the neurons to survive,” Dr. Yuen said.

After treatment, Braelynn may never need medicine for her SMA again.

As Braelynn’s neurologist from infancy, I know how life changing this is. Left untreated, this illness would rob Braelynn of her strength while sparing her intelligence, stopping her from rolling, sitting, crawling, or walking, and eventually causing her to have trouble with eating. It would weaken the muscles around her lungs, leaving her prone to complicated infections and respiratory distress. Most untreated children with SMA do not survive past their second birthday. The damage cannot be reversed. However, with new treatment options for gene therapy, it can be prevented if the child is diagnosed early on.

At her recent neurology clinic visit, Braelynn achieved milestones at 20 months that untreated babies never do. She is talking, using sign language, rolling, sitting, crawling — and pulling to stand. Earlier this year, despite Weissenfluh’s strict safety precautions, Braelynn got croup, a viral infection. Instead of being hospitalized though, which happens often in SMA, Braelynn was able to beat the infection in just three days. I expect her to lead a long and fulfilling life, albeit with more medical visits than the average toddler, including to pulmonology, orthopedics and physical therapy services.

Treatment for Payton

Not too long after Braelynn’s treatment journey began, Danielle Coleman, MD, of Pediatrics Northwest, saw 2-day-old baby Payton for her first appointment, and immediately knew something was amiss: she had low muscle tone, weakness, and no startle reflex. Dr. Coleman urgently referred her parents Paige and Tyler Drennen to the neurology department at Mary Bridge Children’s Hospital, where we confirmed that Payton also had type 1 SMA, the same form as Braelynn and the most common type.

Unlike Braelynn, Payton’s bloodwork made her immediately eligible for the one-time IV gene treatment, Zolgensma. It transfers the missing genetic material directly into cells, carried within the hollow shell of a tiny virus known as AAV9. Since Payton had never been exposed to AAV9, she could move directly to the gene therapy. Although nervous, the Drennens opted for the new treatment.

In February 2020 and, at just 16 days old, Payton received Zolgensma, making her the youngest postnatally diagnosed baby ever to receive the treatment worldwide. That day, Mary Bridge Children’s Hospital also became the first non-university hospital in the entire region (from Wyoming to Alaska) to provide this type of gene therapy. This is even more critical now that Washington state has added SMA to the newborn screening program, allowing babies born in Washington with the condition to be caught as early as possible.

While babies younger than Payton have since received Zolgensma, it was a very special milestone for Payton’s family. She began to move her arms and legs, first while swimming, and then “on land.” Each new gain has been a cause for celebration in the life of this incredibly bright little girl.

Because of our growing neuromuscular program, this year, Mary Bridge Children’s was invited to join the nonprofit Muscular Dystrophy Association as a Care Affiliate. Hopefully, this means that children with SMA and other neuromuscular diseases can find a medical home, support, and treatment team at Mary Bridge Children’s.

Learn more about the genetics and neurology programs at Mary Bridge Children’s.

Your gifts to the Mary Bridge Children’s Foundation allow for families like Braelynn’s and Payton’s to receive innovative care close to home. Make an impact today at Mary Bridge Children’s Foundation.