GCK Hyperinsulinism: Nico’s Story

Nico, now 7 years old, was diagnosed with glucokinase (GCK) HI at Children’s Hospital of Philadelphia (CHOP) after nine months of unsuccessful treatment elsewhere. GCK HI is a rare form of HI that can be especially difficult to diagnose and treat. Some individuals have mild symptoms that can be managed with diet; others, like Nico, are severely affected and struggle to maintain high enough blood sugar to stay safe.

Even after Nico came under the care of CHOP’s Congenital Hyperinsulinism Center, the most experienced center treating HI in the world, things were not easy. It wasn’t until he joined a clinical trial at CHOP that he began to have a more normal childhood.

“Putting him in that trial was the start of things. It made such a huge difference in his life,” his mother, Jury, says.

A scary first nine months

Nico was born at a local hospital near his home in Freemansburg, PA, and, luckily, his low blood sugars (hypoglycemia) were recognized early. Nico was in NICU for the first two weeks of his life, connected with dextrose and glucagon via his umbilical cord to stabilize his blood sugar levels.

Doctors there told Nico’s parents that his hypoglycemia would “just take time” to move into the normal range. For some babies with hypoglycemia, the low sugars are what doctors call “transient” and do resolve on their own. However, for Nico, nothing changed after nine months of around-the-clock feedings (formula and breast milk) as well as high doses of diazoxide. His glucose levels rarely nudged above the mid-50s or 60s mg/dL, which was the target the local pediatric endocrinologist gave his family. A normal blood sugar level is between 70 and 100 mg/dL.

That’s when his mom said, “I’m going to CHOP.”

Once Nico was in Philadelphia, the HI Center team tried the front-line HI medication, diazoxide. Unfortunately, it didn’t completely work for Nico. Genetic testing identified his specific HI type as GCK HI. A GCK HI patient is a rarity even at CHOP, representing only about 2% of cases. Nico needed surgery to remove nearly all of his pancreas (a 98% pancreatectomy) and continuous dextrose delivered through a G-tube to help manage his low blood sugar.

His remaining pancreas was releasing so much insulin that Jury was constantly worried his blood sugar would drop dangerously low. Lanreotide and octreotide, other medications that help some post-pancreatectomy HI patients, didn’t work for him. Other children with GCK HI can use a diet high in carbohydrates to manage hypoglycemia, but Nico developed a severe food aversion and had trouble keeping any food down.

“He would vomit six to 10 times a day,” Jury remembers. “We built a special playpen for him and had towels everywhere to clean up after him. Even the smell of food would make him sick. He had to be upstairs when I cooked downstairs, and we had to eat in a different room."

The clinical trial that turned the tide

Then, in 2019, at age 3, he enrolled in the life-changing research trial to receive an investigational therapy continuously through a pump, similar to how some patients with diabetes receive insulin. The study drug works by increasing glucose levels in the body, with the goal of stabilizing blood sugar levels.

After starting the clinical trial, along with diazoxide given through his G-tube, Nico’s blood sugar levels remained in the safe range. “It was a huge relief,” Jury says. “This investigational drug gave Nico the independence for him to engage in a more normal child’s life.”

Feeding therapy: slow but steady progress

With hypoglycemia as less of a risk, it was time to work on having Nico eat by mouth. Many HI babies are slow to eat orally, and they have to learn chewing and swallowing skills. An oral feeding therapist had been coming to the family home since Nico was 1 year old to help him overcome his complex eating problems.

“He had a psychological block to eating,” Jury says. Initially during therapy, Nico and the therapist would play with his toys at one end of the table while some food would be at the other end. Over several sessions, the therapist then moved the food closer and closer to where they were playing. The therapist put a piece of broccoli in with his toys, just so he would see it. “Then the broccoli would ‘kiss’ his arm, then his cheek,” Jury says. “Nothing was forced. Everything was done at Nico’s pace.”

“It was a years-long process. Slow and steady progress, but there was progress, and that’s what counts. Gradually, very gradually, he started to eat by mouth.”

Nico isn’t a fan of carbohydrates, fruits or vegetables, but these days, he eagerly eats cheese, meat and seafood and will try different foods — gigantic leaps from where he was a few years ago. He still receives G-tube feeds twice a day to supplement what he’s eating by mouth.

Eating by mouth “was a game-changer,” Jury says. “Therapy gave him the space to engage with food and to accept the food. It’s allowed him to have a normal life.”

Thriving at school

Nico is in the second grade in a public school. A private nurse goes with him to check his blood sugar levels and connect his G-tube when needed, although he’s becoming more aware of when he “feels funny” because he’s having a low. 

He eats his packed lunch alongside the other kids, even as his feeding pump is delivering his lunch.

He was diagnosed with ADHD and is having therapy to help him improve his focus. About half of kids with HI are later found to have some type of behavioral or learning issues. Awareness, early diagnosis and treatment can help them keep up with their peers.

“He’s a smart cookie — he tested into the gifted program in math — but he can be hard to re-engage,” his mom says. “Learning to read has been a little harder because it requires more focus.”

Nico’s ADHD hasn’t stopped him from learning everything he can about sharks. “Sharks are just so cool. They have a supercool fin and teeth,” he says, fired up. “Megalodon sharks have the biggest teeth.”

“He’s our hero,” Jury says. “Sometimes if I get sad or worried, Nico will tell me, ‘Everything’s going to be OK.’ He asked if he had to wear his pump forever, and I explained that it has the medicine he needs. He told me, ‘It’s OK. I got this.’ He’s a fighter. It’s hard to describe how proud I am of this child.”