May 23, 2019 07:55 AM
Two Twin Cities parents are using a special diet to help treat their son's rare disease.
It started as a hunch, and now has led to a Mayo Clinic pilot study.
Two-year-old Leo St. Martin was diagnosed with Pompe disease when he was just four months old. This means a complex sugar called glycogen builds up in his organs, and his body doesn't have the right enzyme to break it down.
The build-up can lead to organ failure. In Leo's case, his heart tissue was thick and swollen.
"His heart had gotten so big, it was crushing his left lung," Leo's mother Anne St. Martin said.
"They told us, 'Don't expect him to eat on his own, to breath on his own, to walk,'" said Leo's father, Denis St. Martin.
The standard treatment for Pompe disease is called enzyme replacement therapy. Every week, Leo gets an infusion of a synthesized version of the missing enzyme.
However, the results were underwhelming. Leo still had heart problems, as well as trouble eating and breathing.
Dr. Marc Patterson at the Mayo Clinic said that can be a common hurdle.
"He did have a long period when he was receiving the replacement therapy and he really wasn't making progress," Patterson said.
In February 2017, Leo's parents started experimenting with his diet to try to do what enzyme replacement therapy could not. The St. Martins imposed a strict ketogenic diet: high fat and limited sugar and carbs.
"It stops fueling the disease," Denis St, Martin said.
The St. Martins said they believe the science makes sense. By feeding Leo a high-fat diet, they change his body's main fuel sources from sugar and carbs to fat. That change makes it easier for Leo to break down the amount of harmful glycogen building up in his tissues and organs.
"He's on a 2-to-1 ration, so he has two fats for every carb," Denis St. Martin said.
Amazingly, what Leo's parents are doing seems to be working.
"I think I noticed his strength and energy start to improve," Anne St. Martin said.
"We saw all the things start to happen they told us would never happen," added Denis St. Martin.
Cardiologist Jonathan Johnson at the Mayo Clinic said Leo's heart condition has improved. The swelling is reduced and his heart is functioning normally.
"If I showed his echocardiogram to any other cardiologist, they'd tell me it's normal," Johnson said.
The improvement is so significant that Leo's doctors are launching a pilot study surrounding Leo's diet. They want to know whether it might help other patients like him.
Leo is still receiving the enzyme replacement therapy, so his doctors want to know just how much a difference the diet is actually making.
"Clearly he is doing much better since he's been on the diet," Patterson said. "We think that's very encouraging, it's very strong circumstantial evidence."
The pilot study is expected to launch later this year.