A Rare Genetic Condition with an Even Rarer Treatment

Four-year-old Payton Patterson is much like other children her age – she loves playing dress up, spending time with her parents and two older siblings and watching Paw Patrol.

However, within Payton’s DNA lies a rare genetic disease called CLN2, a type of Batten disease, which is a childhood neurogenerative condition that occurs in around 6 in every 100,000 births.

The youngest daughter of Keith and Amanda Patterson, Payton had her first seizure in May 2022 at the age of three.

After two grand mal seizures the next month, she was diagnosed with epilepsy.

Payton also wasn’t progressing normally with her speech at that age, but with the COVID-19 pandemic in full swing, the Pattersons knew of many other families with young children who were experiencing delayed developmental milestones as well.

But after she began experiencing seizures every three to five days for months after being put on anti-seizure medication, the family started to wonder if there was more to Payton's condition.

“Something in my gut said, ‘something is wrong’,” Amanda Patterson, Payton’s mother, said.

Following her instincts, Amanda Patterson searched for another opinion and found the University of Michigan Health C.S. Mott Children’s Hospital.

A rare genetic disorder

Payton saw Mott pediatric neurologist Eric Armour, M.D., who ordered genetic testing to rule out any uncommon causes of seizures.

The results came back positive for the CLN2 variant of Batten disease, which involves a gene mutation preventing production of an enzyme that limits the body’s ability to get rid of cellular waste. This buildup of cellular waste may cause seizures, movement disorders, regression of developmental milestones and eventual vision loss. 

After the diagnosis, Payton and her family met with the pediatric genetics team at Mott to discuss treatment options, which included Elizabeth Ames, M.D., Ph.D., a clinical assistant professor in the pediatric genetics division.

The first step of treatment, Ames explains, required a neurosurgeon to surgically implant “a port which acts as a permanent access point in her brain.” Payton then receives an infusion of an enzyme replacement medication through the port, into her brain, every two weeks to slow the loss of her motor function.

This is the first enzyme replacement therapy administered to a Michigan Medicine patient, and treatment for Batten disease is rare overall.

“There are probably only 100 people in the country who get this medication,” Ames said.

Payton went from her diagnosis in early April 2023 to receiving her first infusion several weeks later on April 24.

The incredible speed from diagnosis to treatment was no small feat.

Payton’s infusions require coordination from a variety of services including neurology, neurosurgery and genetics, as well as a biweekly admission to the pediatric intensive care unit.

Her care involves a team of nurses including nurse practitioners with specialized certifications required to administer medication directly into the brain.

“There are so many people who really have just said, ‘what this kid needs, we’re going to do,” Ames said.

“It was just an incredible amount of work from so many people. We’re really thankful that it happened so quickly for her.”

An ‘unreal’ team

The Pattersons and their pediatrician offer high praise for the teamwork between Mott pediatric neurologist Armour and genetics expert Ames to arrive at Payton’s diagnosis.

“It was genius for Armour to pinpoint what he really wanted to look for in the genetic testing and to even try to test for something so rare knowing very little symptoms,” Keith Patterson said.

“Between the two of them figuring that out, it’s a once in a career diagnosis,” Amanda Patterson added.

During the brain infusion treatments, the Patterson family has found comfort with their treatment team at Mott.

“This team is unreal. There is compassion in every interaction and there is relentless passion to help give Payton the best life we possibly can, and the only way to do that is with continued success with infusions. The team has helped us out this far and we are hopeful for the future,” said Amanda Patterson.

“They want to work with us and ask us what they can do to make this better,” her husband added. “They make us feel like they don’t have another patient.”

Ames and the Pattersons also credit “nursing champion”, Caitlin Gotham, M.S.N. as essential for PICU infusions.

Gotham is involved in complex care coordination of the many service providers involved in Payton’s treatment and the rapid process improvement to make her infusions the best they can be for Payton and her family.

“We are lucky to have Payton here for her treatment, and we are hoping to give the best care possible for her and future patients like her,” Gotham said.

Reaching out for support

For other families with a child suffering from a rare disease, the Pattersons recommend support groups and using social media to connect to fellow families.

“Reach out to people that have been there. You wouldn’t think that it would help, but it does,” Keith Patterson said.

“I found someone who knows exactly what I’m going through,” Amanda Patterson added.

Talking to other parents has also helped the Pattersons get an idea of when infusions start to take effect. It varies patient to patient, but halting symptoms may take several months.

“If your child has seizures, unexplained, uncontrollable, get genetic testing,” Amanda Patterson said. “It should be the first thing, yet it’s not something that’s really talked about.”

A destination for rare disease treatment

Payton’s diagnosis came just a month before Michigan Medicine was recognized as a Rare Disease Center of Excellence by the National Organization for Rare Disorders in May 2023.

Ames, who serves as the co-director of the new center, says this recognition indicates “Michigan Medicine is the place for patients with rare diseases, not only to receive a diagnosis, but also to receive treatments.”

The center strives to improve the lives of children and adults with rare diseases, a patient population that is often overlooked, throughout Michigan and the world.

When discussing the future of rare disease treatments, Ames has high hopes for gene therapy.

“In the next five to 10 years, we will have a revolution of gene therapy, and this type of really advanced complex medicine will become much more common,” she said.

“Payton will continue to have health concerns, but her disease advancement with be much, much slower as compared to if she was untreated,” Ames added.

“She will, hopefully, in her lifetime, be able to receive gene therapy.”

For now, the Pattersons are adjusting to their new norm.

The family recently purchased a camper van for the whole family to travel together biweekly from their home in west Michigan to Ann Arbor while seeing sights and getting some rest along the way.

[VM/Newswise]

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