Cook Children's International Program

Endocrinology and Diabetes

Cook Children's Endocrine and Diabetes program treats infants, children and teens with conditions that are caused by or affect the hormonal balance of the body. We understand the importance of working together and that's how we approach the care of our children.

Hyperinsulinism Center

Cook Children's Congenital Hyperinsulinism Center is the only one of its kind in the Southern United States, and only the second in the country. The center is led by medical director Paul Thornton, M.D., one of the nation's few physicians with extensive clinical and research experience in congenital hyperinsulinism (CHI).

CHI is a rare and severe disorder that frequently causes persistent hypoglycemia in newborns and children. The estimated incidence of CHI is one in 50,000 live births, resulting in between 80 to 120 new CHI patients each year. Infants with uncontrolled hypoglycemia caused by CHI are at risk for seizures or permanent brain damage. Early identification and screening are key factors in preventing irreversible damage and improving quality of life.

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Congenital hyperinsulinism

There are many types of congenital hyperinsulinism (CHI), each treated differently and with different outcomes. The CHI diagnoses that we treat are listed here.

Genetic forms of congenital hyperinsulinism

There are many genetic forms of CHI with more being discovered each year. Typically, 60 percent of patients with genetic forms will present in the first week of life with hypoglycemia. These patients will have hypoglycemia that requires a combination of feeding frequently and/or glucose infusion to keep the blood glucose above 70 mg/dl. Some may respond to diazoxide, but more than 50 percent will not and will require surgery to cure the hypoglycemia. Current best practices suggest that pediatric endocrinologists make a diagnosis of the different forms of CHI and determine whether the infant has autosomal recessive diffuse hyperinsulinism or non-mendelian genetic focal disease. This diagnosis is confirmed by running genetic and special imaging studies, which are only available in special hyperinsulinism centers with research studies and a multidisciplinary CHI team, like Cook Children's Hyperinsulinism Center. Early identification and treatment of these genetic forms of CHI is critical to preventing the 20-40 percent incidence of brain damage seen in these children.

Diffuse hyperinsulinism

Diffuse hyperinsulinism is a form of ATP sensitive potassium channel congenital hyperinsulinism (Di-KATP HI) caused by autosomal recessive mutations in ABCC8 or KCNJ11. Infants diagnosed with Di-KATP HI have an abnormal pancreas where all beta cells are abnormal and secrete insulin. When medical therapy fails, surgery is usually required to remove up to 98 percent of the pancreas. Most of these patients will develop diabetes or persistent hypoglycemia and will need to be managed by an endocrinologist long-term.

Focal hyperinsulinism

Focal hyperinsulinism is another form of ATP sensitive potassium channel congenital hyperinsulinism (Fo-KATP HI) that is caused by an unusual genetic abnormality. These infants have an autosomal recessive mutation in ABCC8 or KCNJ11 from the father and a loss of the normal maternal allele. This causes a small part of the pancreas to secrete insulin during hypoglycemia. Because a small portion of the pancreas is affected while the rest of the pancreas is normal, diagnosing patients with Fo-KATP HI allows us to identify which part of the pancreas is affected and remove it. As a result, some patients are cured and have a very low risk of diabetes.

Cook Children's uses an investigational new drug combined with a PET-CT scan to diagnose focal lesions in children with congenital hyperinsulinism. Because only a small amount of the pancreas is affected with focal congenital hyperinsulinism (CHI), it can be cured with surgery. However, special testing using the investigational drug 18F DOPA, as part of a clinical research trial, combined with a PET-CT scan is needed. Once located, the surgeon can remove the focal lesion. This leaves most of the normal pancreas behind, which may prevent the development of diabetes and cure the child.

Glutamate dehydrogenase hyperinsulinism

Glutamate dehydrogenase hyperinsulinism (GDH-HI) is the second most common type of hyperinsulinism and may be referred to as protein sensitive hypoglycemia. With GDH-HI, the pancreas releases an abnormal amount of insulin in response to both fasting and protein ingestion. Children diagnosed with GDH-HI have elevated ammonia levels at all times and low blood sugar levels after eating protein and after an overnight fast. Most diagnoses occur in children more than 3 months old when their diet becomes exposed to a higher protein intake. These children usually respond to diazoxide and rarely need surgery.

Glucokinase hyperinsulinism

Glucokinase hyperinsulinism is one of the least common forms of CHI. It is caused by activating mutations in the glucokinase gene, the glucose sensor of the beta cells. With this form of CHI, the beta cells do not recognize that the glucose levels are ‹70 mg/dl so they continue to secrete insulin and cause hypoglycemia. The age of onset varies from newborn to adulthood. These children often respond to diazoxide and only the most severe will require surgery, which is a 98 percent pancreatectomy.

Transient neonatal hyperinsulinism

Transient neonatal hyperinsulinism (TNHI) is one of the most common forms of hyperinsulinism (HI) with an estimated 1:10,000 babies affected. Typically, hypoglycemia begins within 24 hours of birth and can last from three to 10 days up to six months. Often this form of CHI is caused by a diabetic mother, perinatal stress, perinatal hypertension, intrauterine growth restriction (IUGR) or a large for gestational age (LGA) pregnancy; however, some babies appear to have no risk factors.

The hypoglycemia may be mild, with hypoglycemia occurring two to four hours after eating or it may be more severe with hypoglycemia occurring despite intravenous glucose infusion and/or high-calorie feedings every three hours. Although TNHI is temporary, it can cause brain damage if left untreated. In order for infants with TNHI lasting longer than seven days to be discharged from the medical center, they will need treatment with diazoxide and proof that the illness is controlled by demonstrating the ability to fast for eight to nine hours. Most of these patients will need regular visits to an endocrinologist specializing in hyperinsulinism for the next six to 12 months. Hypoglycemia will typically resolve itself during that time frame.

Endocrinology and Diabetes team

Paul Thornton, M.D. – Medical Director, Cook Children's Endocrine and Diabetes Program and Hyperinsulinism Center
Specialties: Endocrinology

Education: University College, Dublin, Ireland
Residency: Temple Street Children’s Hospital & The National Maternity Hospital, Dublin, Ireland
Fellowship: The Hospital for Sick Children, Toronto, Ontario, Canada

Awards/Recognition: Super Doctors® Texas 2015


Don Wilson, M.D. – Endocrinologist
Specialties: Endocrinology

Education: University of Mississippi, Oxford, Miss.
Residency: Baylor Affiliated Hospitals, Houston, Texas
Fellowship: Baylor Affiliated Hospitals, Houston, Texas

Awards/Recognition: Living Magazine: Best Doctors in America List 2015-2016


John Dallas, M.D. – Endocrinologist
Specialties: Endocrinology

Education: University of Tennessee, Center for the Health Sciences, Memphis, Tenn.
Residency: University of Kentucky Medical Center, Lexington, Ky.
Fellowship: Children’s Hospital of Pittsburgh, Pittsburgh, Pa.

Awards/Recognition: Super Doctors® Texas 2015


Jill Radack, M.D. – Endocrinologist
Specialties: Endocrinology

Education: University of Colorado School of Medicine, Aurora, Colo.
Residency: The University of Texas Southwestern Medical Center, Dallas, Texas
Fellowship: The University of Texas Southwestern Medical Center, Dallas, Texas

Awards/Recognition: Super Doctors® Texas 2015

Diagnoses treated:

Finding a cure for hyperinsulinism
Cook Children's has been able to cure babies with hyperinsulinism cured using 18F DOPA, a new drug used to diagnose focal lesions in children with the rare disease Learn more.

Cook Children's hyperinsulinism is in the news. See one family's story here.

Cook Children's Hyperinsulinism Center is one of only two programs in the country, and has an international reputation for achieving positive outcomes.

Our endocrine patients have access to the most advanced diagnostic tools and participation in the latest research studies.

A specialized lipid clinic, known as the Risk Evaluation to Achieve Cardiovascular Health (REACH) Clinic, is available to treat children at risk for future heart disease and type 2 diabetes.

Referral forms

Need help referring a patient?
Please call the International Patient Services department at +1-682-885-4685, send faxes to +1-682-885-2557, or email