At just 5 months old, Sienna Holtvluwer suffered severe respiratory failure at her family’s home in Conklin, Michigan.

Her parents, Shayn and Emily Holtvluwer, rushed her to Spectrum Health Helen DeVos Children’s Hospital, where doctors worked diligently to determine the cause.

After weeks of tests and exams, they diagnosed Sienna with spinal muscular atrophy.

“I Googled SMA and I had a very hard time with it,” Emily said. “It didn’t seem like very good news.”

Emily and Shayn began meeting with doctors and specialists in hopes of learning more.

“I remember doctors saying that we could take her home and love her,” Shayn said.

Spinal muscular atrophy is a genetic condition that causes the muscles to become weaker and stronger. It can affect a child’s ability to sit, crawl, walk, eat and breath.

The family soon met with Jena Krueger, MD, pediatric neurologist at Helen DeVos Children’s Hospital.

“Once we met Dr. Krueger, it eased our worries,” Emily said. “She gave us some answers, along with treatment options right away. We were even told she would live a good life.”

Sienna received her first treatment of the drug Spinraza and transitioned to Zolgensma, gene therapy.

If you ask Dr. Krueger about gene therapy, she’ll tell you it’s a game changer.

“We are on the leading edge of all of this,” she said. “If you look at kids who transition from Spinraza to gene therapy, they are stronger, healthier and hitting better milestones overall.”

Sienna spent 43 days in the pediatric critical care unit before she could return home.

Over the next year, she progressed incredibly well. She didn’t require a single overnight stay in the hospital.

“We took care of her at home and adjusted to our new normal,” Emily said.

Sienna would also receive in-home occupational therapy and physical therapy to work on movement. She visited Dr. Krueger every few months for checkups.

Keep on moving

A year later, Sienna would become a big sister.

When her brother, Wesley, was born, Shayn and Emily immediately requested a test for spinal muscular atrophy.

It’s a genetic condition that can be passed down from parents to children, so doctors knew Wesley could test positive, too.

“We had no family history … no clue at all,” Emily said. “It’s genetic and you are born with it.”

Wesley tested positive. He received his first treatment of Zolgensma at just 10 days old, following a similar path as his big sister.

But spotting the condition so early in Wesley’s life likely made a difference.

“Wesley doesn’t show any of the normal traits of a child with SMA,” Dr. Krueger said. “He has slightly weak reflexes, but that’s it.

“His sister, Sienna, has limited mobility and uses a walker to get around,” she said. “She’s learning about her limitations, but just keeps on moving.”

‘Both little miracles’

The Holtvluwer family lives on a farm in their small village, just north of Grand Rapids.

They have four goats, a cow, two dogs and a cat.

“We plan to add even more animals to our family in the future too,” Shayn said.

Sienna’s room is decorated with princesses and rainbows galore, while Wesley has a cozy man cave of his own.

Almost every day, Sienna has a different bow for her hair. She lines them up at the end of her bed, organizing them by color and design.

“It’s literally a different princess every day,” Shayn said. “She’s something special for sure.”

Sienna isn’t shy about showing the world her bravery. She attends preschool, where she uses a wheelchair or standing device.

Emily works two days a week and stays home with Wesley on other days. She has in-home nursing care to help, too.

“I never thought we would have two children with a genetic condition that is considered the No. 1 genetic killer of babies,” Emily said. “Having the two of them live past the two-year mark of traditional life expectancy is amazing. They are both little miracles.”

‘A familiar face’

Every three months, Emily brings Sienna and Wesley into the pediatric neurology clinic at Helen DeVos Children’s Hospital for checkups.

At a recent visit to the hospital, Sienna sat quietly as she munched on fruit snacks and waited patiently to see Dr. Krueger.

The wheels on her wheelchair are decorated with princesses, unicorns, flowers and rainbows. Her name is on one wheel, painted in glitter.

“What does a unicorn say?” Emily asked as they wait to see the doctor.

“Neehhh!” Sienna exclaimed with a laugh and a squeal.

As Dr. Krueger entered, the excitement picked up.

“Look at those fine motor skills she is developing,” Dr. Krueger said, giving Sienna a high five. “Awesome, girl!”

Sienna is a familiar face in the children’s hospital, and she lights up the faces of the clinical staff on a regular basis, Dr. Krueger said.

Later, physical therapists joined Sienna in the hallway, where she practiced her steps and walking.

Each day, Sienna spends up to two hours in her gate trainer and about two hours in her stander while she’s at school.

“Go baby go,” Dr. Krueger said. “You did so good, Sienna.”

As she made her way down the hallway, one step at a time, the physical therapy team gave her a standing ovation.

“She’s gotten a lot better with putting weight down on her feet when she takes the steps,” Dr. Krueger said. “The marks on the floor are a six-minute walk. And Sienna is going to do it someday.”

Challenges and hope

When they returned home, Sienna and Wesley sat and played with princesses and pickup trucks on the living room floor.

Like all siblings, they argued over who would play with what.

“I always remember Dr. Krueger saying, ‘You are going to need to tell her no someday, because she is going to be so smart and will want to push your buttons,’” Emily said.

And indeed, Sienna likes to explore and get into things.

“We do really have to tell her no a lot,” Emily said.

Sienna and Wesley keep Emily and Shayn on their toes, but they all love every moment of it.

“It’s surreal to think they both could be immobile or even no longer with us at this point,” Emily said. “These treatments are giving them more of a normal life. And they’re experiencing the other fun things kids should be doing.”

Sienna loves her gate trainer. It’s like a walker with a bicycle seat.

“I want to chase Wesley, I want to race Wesley,” she said.

She’s practicing her volume and strength of voice at school now, too.

“Her new one? How high can you count,” Emily said. “She counted to 20 for the group of doctors and physical therapists. All in one breath.”

She even went snowmobiling with her dad for the first time this winter.

“We’re hoping our kids will be able to live a normal life like any other family,” Emily said. “But we know we have challenges ahead.”

Even so, there’s much hope on the horizon for these two siblings.

“It’s not an awful diagnosis anymore,” Emily said. “Treatment has really changed the outcomes for both kids. And nothing is going to get in their way.”