Hyperinsulinism is a rare genetic disease in which the pancreas produces too much insulin, driving blood sugar levels dangerously low and depriving the brain of important fuels it needs to function. It affects about 1 in 20,000 to 30,000 newborn babies each year.

"The treatment of congenital hyperinsulinism is very complex," said Paul Thornton, M.D., medical director of Cook Children's Hyperinsulinism Center. "It's really important that patients with rare diseases have access to multidisciplinary teams such as are at Cook Children's Hyperinsulinism Center where the approach and the experience of the team members caring for these patients results in better outcomes with shorter lengths of stay, getting the patient's home to their families as fast as possible."

The Centers of Excellence designation comes on the heels of Cook Children’s Hyperinsulinism Center’s 10^th anniversary, which was celebrated in November 2020. Dr. Thornton built and leads the program at Cook Children’s, which includes a team of physicians specialized in endocrinology, pediatric surgery, neonatology, neurology, gastroenterology, pathology and radiology. The team is supported by a dedicated CHI nurse practitioner, social worker, clinical therapist, child life specialist, nutritionist and feeding and speech therapists.

“There are some superb institutions known for providing excellent HI care and participating in groundbreaking research, yet until now there has not been a review process or certificate awarded to these institutions for the care of those with HI,” said Julie Raskin, executive director of Congenital Hyperinsulinism International.

The awarded centers are:

• Hyperinsulinism Center at Cook Children’s Medical Center in Fort Worth, Texas
• Congenital Hyperinsulinism Center at the Children's Hospital of Philadelphia, PA
• Great Ormond Street Hospital Congenital Hyperinsulinism Service in London, in the United Kingdom
• Charite-Universitatsmedizin Berlin and the University Children's Hospital Duesseldorf partnership in Germany
• Collaborative Alliance on Congenital Hyperinsulinism headquartered in Magdeburg, Germany
• Northern Congenital Hyperinsulinism Service in Manchester and Liverpool, in the United Kingdom

Like a lot of boys growing up, Dr. Thornton’s interest centered on athletics. He calls himself a “sports fanatic,” playing rugby, cricket, tennis and swimming. As a kid, he played more than studied.

So when Dr. Thornton told his guidance counselor in high school that he wanted to become a doctor, the counselor told the man who would become a world expert in a rare disease that he needed a back-up plan.

What the guidance counselor didn’t understand just yet was that Dr. Thornton’s focus from an early age was on science and medicine. Dr. Thornton saw something in himself that nobody else saw.

“When I said I wanted to be a doctor they told me I should have a backup plan,” Dr. Thornton says now with a twinkle in his eye. “So that was always fascinating to me. I wasn’t the guy people thought was the most intelligent person in the class. Now I’m a world expert in a disease. Once I became a doctor, I realized where my true passion was and I followed it.”

Congenital Hyperinsulinism

Dr. Thornton resides at Cook Children’s as the medical director of the Endocrine and Diabetes Program and the Hyperinsulinism Center. He played a vital role in establishing the first two centers for congenital hyperinsulinism (CHI) in the nation.

His congenital hyperinsulinism program at Cook Children’s celebrates its tenth anniversary this year. The genetic forms of HI affect only between 80 and 120 babies each year. For those affected by the rare condition, it can be a life-changing event. Without an accurate diagnosis, children face living with seizures and permanent brain damage.

The program gives many patients an opportunity for a cure because of the expert staff and the use of an investigational new drug called 18F DOPA in combination with a PET-CT scan to more accurately diagnose and treat HI.

The 18F DOPA/PET-CT scan serves as a diagnostic test that has altered the treatment and even led to cures for children with certain forms of hyperinsulinism. Cook Children’s remains the only facility in the south and the second in the country to use 18F DOPA – an investigational drug – in combination with a PET-CT scan to diagnose focal lesions in children with congenital hyperinsulinism.

Dr. Thornton leads a team of physicians specialized in endocrinology, pediatric surgery, neonatology, neurology, gastroenterology, pathology and radiology. The team is supported by a dedicated HI nurse practitioner, social worker, clinical therapist, child life specialist, nutritionist and feeding and speech therapists.

At the heart of the program is Dr. Thornton, one of the most recognized and respected HI specialists here and around the world.

The Expert

To show what a leader he is in the field, Dr. Thornton’s served as lead author for an article titled “Recommendations from the Pediatric Endocrine Society for Evaluation and Management of Persistent Hypoglycemia in Neonates, Infants and Children.” This article established the groundwork in creating new screening for physicians to recognize and manage neonates at increased risk for a persistent hypoglycemia disorder.

The guidelines help physicians recognize the symptoms of uncontrolled hypoglycemia caused by CHI who are at risk for seizures or permanent brain damage without early identification and screening.

Dr. Thornton’s recognition as a leader earned him one of the first two endowed chairs at Cook Children’s. He’s a recipient of the Rare Disease Hero award, which recognizes only five physicians each year for groundbreaking research and treatment in the rare disease community.

He’s come a long way from what Dr. Thornton calls his “quirky story.”

Growing Up

Dr. Thornton grew up in a middle-class family in Ireland. His grandfather ran the water department for the government, responsible for water purity for the country. His father did not go to college but rather became a businessman.

Little did Dr. Thornton know how hard his father worked to give his children an opportunity to continue their education.

“I went to a private Catholic school. This is going to sound really strange, but I did not know it was a private school,” Dr. Thornton says while laughing at the thought. “You know in Ireland, everyone wears a school uniform. It’s not like in the States where only private school kids wear one. And it’s not like here, where there’s a private school at every stone’s throw. It just never dawned on me. Later my father said, ‘Do you know how hard we had to work to pay for that school?’”

Maybe it’s that example of hard work that led to Dr. Thornton earning his medical degree by the age of 23, the culmination of a childhood dream.

“It’s funny because there was almost nothing else I ever wanted to be. I knew from the age of 12 that I wanted to be a doctor,” Dr. Thornton said. “I think it was probably because of our family practitioner (Dr. Brendon Deasy). Dr. Deasy was a really good friend of the family, so I got to know him very well. I went to see him professionally every year. I realized that the work of a doctor was a really nice career. You got to meet new people every day. You got to help people. He is probably responsible for showing me what a great job being a physician could be.”

Dr. Thornton went to college without a backup plan. He knew once he got into university and could focus on studying to be a doctor, he would excel.

A Pediatrician

Once his clinical rotations began, Dr. Thornton decided early on that pediatrics was for him.

“When you work with children, they are restorative. You can’t come in grumpy.. You end up having fun doing your day’s work,” Dr. Thornton said. “It never seemed like a lot of fun dealing with adults all the time.”

What did seem like fun was endocrinology. Although his focus came about through a bit of circumstance and travel.

In medical school, Dr. Thornton excelled and “fell in love with learning.” He begins to get noticed too and that eventually led him to Great Ormond Street Hospital (GOSH) for Children, the oldest and one of the most prestigious pediatric hospitals in the world. This job was part of a job exchange with residents from the Children’s Hospital of Philadelphia, so Dr. Thornton headed to the States for a year

Dr. Thornton pauses for a moment thinking about his arrival in the United States.

“I only spent 28 years of growing up in Ireland. I left for England at 28 and came to the U.S. at 29. So actually, I spent less than half my life in Ireland. Wow!”

At CHOP, Dr. Thornton met the mentors who changed his life. He learned about endocrinology and specifically, hypoglycemia. “It didn’t take me long to determine that’s what I want to do with the rest of my life,” he said.

“I was very lucky that I trained at the only place, at the time, that had that sort of hypoglycemia program,” Dr. Thornton added. “So two of the doctors (Lester Baker and Charles Stanley) out of my four attending physicians were the world experts in hypoglycemia. It was just fascinating. The patients we were seeing were very difficult kids to manage.”

At the end of his year commitment, Dr. Thornton planned on returning to England, but CHOP offered him a fellowship to stay. He wrote GOSH a letter that said he wasn’t going back to London.

Returning to Great Ormond Street meant Dr. Thornton couldn’t stay on his new chosen career path. He wanted to learn more about treating children with hypoglycemia. Dr. Thornton did return to Ireland from 1996-1999 but eventually went back to CHOP where he remained until 2002 when he got a call from a recruiter.

Welcome to Cook Children’s

Dr. Thornton admits now he’d never heard of Cook Children’s or even Fort Worth when approached about a new job. He turned the recruiter down. Then a few months later, Dr. Thornton presented a paper at a Pediatric Society meeting. The recruiter showed up to hear him speak and invited Dr. Thornton to breakfast for one final pitch.

The recruiter showed Dr. Thornton pictures of the medical center and information about the institution. They ended up talking for four hours.

Following a trip to Fort Worth and a visit to Cook Children’s, Dr. Thornton accepted the role of medical director of Endocrinology.

“Now I still had so much to do. When I got here there were only two doctors. The waiting time was something like nine months,” Dr. Thornton said. “We had to do a lot of work to get the place how I wanted it. Everyone was good people and everyone was working hard. They just needed new leadership and some organization. So the first two or three years was building the program, hiring nurse practitioners and doctors. I focused on the organizational things and developing protocols.”

Soon, the department blossomed and Dr. Thornton became very busy not only as an administrator but seeing patients. However, something remained that lurked in the back of his mind since his arrival at Cook Children’s.

“I reached a position where I had time to think about my future here in Cook Children’s, ‘I had a skillset and focus on hypoglycemia and congenital hyperinsulinism (CHI). I decided to approach the hospital and say, ‘I'd like to set up a new hyperinsulinism center and develop a surgical program for the babies with HI.’ We wrote a proposal and it was like ‘Boom!’ They said, ‘yes.’”

Building a Program

After helping to launch the first such program in the nation, Dr. Thornton knew what he wanted when he began the second one at Cook Children’s. He brought a nurse coordinator/ nurse practitioner, Lisa Truong, CPNP-AC, to help him with the day-to-day operations.

“When Dr. Thornton asked me to join, I was very excited. It was a challenge to build a program from scratch. Ten years later, it’s still a challenge but I love it. All the kids we see are completely different because it’s such a rare condition. No kids present the same, which I like because it keeps me on my toes. I have learned so much from Dr. Thornton throughout these 10 years. He is an awesome boss and a great mentor."

Over the next three to five years, the program continued to grow and build. Cook Children’s showed their support for the program by naming Dr. Thornton one of the first two endowed chairs in the history of the program. Everything clicked.

Even after all this time, nothing thrills Dr. Thornton more to give good news to the families he treats. He continues to carry on a tradition of taking pictures with his families and marvels at their excitement when things go well.

“They realize that ramifications of what life means for them now that their child’s cured,” Dr. Thornton said. “A lot of these families don’t understand what it will mean to their life until it happens. And then it’s a big shock when they get home and realize, ‘Oh my God, I don’t have to check on my baby’s blood sugar eight or 10 times a day. The difference is so huge. You can just see how very happy the family is when there’s a cure.”

If only that guidance counselor could see him now.

But in the days after her birth, enthusiasm turned into fear as baby Ella began to show signs that something wasn’t right.

“She would get jittery. She would scream and she was constantly hungry,” said Carol.

Doctors at the Tucson hospital where Ella was born quickly realized that the little girl with a full head of hair had dangerously low blood sugar, also known as hypoglycemia. Ella couldn’t go home and that big Christmas celebration, along with everything else in her life, now seemed in doubt.

Ella’s caregivers tried several different treatments and when nothing worked, they began to suspect Ella had a rare disease called hyperinsulinism (HI). Hyperinsulinism occurs in about 1 in 50,000 babies. If uncontrolled, it can cause seizures and permanent brain damage.

“The doctors in Tucson did a great job diagnosing Ella’s hyperinsulinism, which was quite severe. They called us knowing about our work with the 18F DOPA PET scan and transferred her here,” said Paul Thornton, M.D., medical director of Cook Children’s Hyperinsulinism Center, one of the top such centers in the world.

Cook Children’s is one of only two institutions in the country to offer an HI program. It’s also one of the only places using the new investigational drug 18F DOPA. When combined with a PET-CT scan, the drug gives doctors a way to treat and even cure patients with few to no side effects.

The Vallecalle family received the call in late November that it was time for Ella to go to Texas. They would be traveling with Cook Children’s Teddy Bear Transport team.

“I was so nervous about leaving my son and also about what we were going to find out about Ella’s condition,” said Carol. “Then all of the sudden, I see these people in blue jumpsuits. There’s this beautiful Texan woman with her big, thick accent and she’s like ‘How y’all doing?’ and I just knew we were going to be fine.”

Carol rode with Ella on the plane to Texas and when they arrived at Cook Children’s, Dr. Thornton and his team got right to work. Using the 18F DOPA drug and the PET-CT scan, they were able to pinpoint the exact location in the pancreas that was causing Ella’s low blood sugar. They were also fairly certain that she had a form of HI known as focal disease, meaning there’s was a chance she could be cured.

“About half of the babies born with HI who are resistant to medical therapy have focal disease which we can treat and cure. The other half has diffuse disease which means they will have persistent hypoglycemia throughout their lifetime,” said Dr. Thornton.

One week after she arrived at Cook Children's, John Uffman, M.D. performed surgery on Ella. Using results from the PET-CT scan, he removed a small portion of the pancreas where a lesion was triggering her HI. She recovered quickly and days later underwent a 16-hour fast. Without any food for that extended period of time, Ella was able to maintain a healthy blood sugar level and her body was able to make ketones, molecules that should be produced during periods of low food intake.

Ella was officially cured.

“I never saw this day coming,” said Carol. “She’s going to have a normal life. She’s going to be able to travel and fall in love and do all of things that she wants to do. It’s a blessing.”

Dr. Thornton is also thrilled about the good news.

“It’s a really big deal for a baby like Ella to be cured because this disease is very serious. The new 18F DOPA drug and PET scan have really made a difference in how we are able to treat these HI patients. In the past, we might have cured a patient but we would have had to remove much more of the pancreas causing almost certain diabetes after surgery.”

Not only are doctors able to offer a cure without the threat of diabetes, they’re also able to send children home much faster than before. Within two weeks, Ella was able to leave Cook Children’s HI free. Before 18F DOPA and the PET scan, Dr. Thornton says most children would be in the hospital for 40 to 50 days.

“I’m just so excited to be home for Christmas,” says Carol. “When we left Arizona, we were fully expecting to be in Texas for a month or more. My son was worried that Santa wouldn’t find us.”

Santa will know exactly where to find the Vallecalle family. For the first time in her life, Ella went home Dec. 15. They will spend Christmas with their family.

More about Cook Children's Hyperinsulinism Center

One of only two such programs in the nation Cook Children's Hyperinsulinism Center uses a specialized team approach to treat this rare disease. Hyperinsulinism affects many areas of the body, so to truly treat the disease, each child is seen by top physicians, nurses, researchers and specialists in the field. These medical professionals have spent additional years of intense study and have dedicated their practice to focusing on hyperinsulinism so that your child has access to the medical care that treats all the symptoms. It is this level of treatment that has helped earn our program a distinguished international reputation for extraordinary care and achieving positive results.

"I would hear that song 'I'll be home for Christmas' in my head, and I'm like, 'I'm not going to be home,'" said mother, Carol Vallecalle.

It was a tough notion for Vallecalle to accept, but not as tough, she says, as what her 6-week-old daughter Ella has been through.

See the full story here.

Paul Thornton, M.D. is the medical director of Cook Children’s Hyperinsulinism Center, one of only two such centers in the U.S. and the only one in the southern portion of the country. He has dedicated his life to researching and treating congenital hyperinsulinsim (HI), and in turn has helped improve the quality of life for countless children.

Dr. Thornton’s work is so well respected he was recently named a Rare Disease Hero by Rare Disease Communications. The award recognizes five physicians each year for groundbreaking research and treatment in the rare disease community.

“Rare Disease Communications is proud to be honoring these real-life heroes,” said Chris Davis, president of Rare Disease Communications. “This is, indeed, a rare opportunity to applaud the silent victories that mean so much to patients and families.”

In addition to the Rare Disease Hero award, Dr. Thornton was also recently honored at the 2016 sugar sHIndig at the Fort Worth Science & History Museum where he was given the Be My Sugar Medical Excellence Award by Congenital Hyperinsulinsim International (CHI).

“It’s an honor to be recognized by the leaders in the congenital hyperinsulinism community,” said Dr. Thornton. “As we continue to treat children from across the country and the world, we’re excited to share information about our program and the excellent team providing quality, family-centered care.”