Oral Medications Can Replace Insulin for Many With Rare Neonatal Diabetes

Presence of genetic mutations signals the ability to switch treatments

WEDNESDAY, Aug. 2, 2006 (HealthDay News) -- Researchers have very good news for most people who were diagnosed with diabetes in infancy: There's a good chance you can switch from injected insulin to an oral medication.

And there's more good news: Those who switch to the oral medication known as sulfonylureas don't appear to have the complications that can trouble those who take insulin, according to two new studies in the Aug. 3 issue of the New England Journal of Medicine.

"Patients diagnosed with diabetes in infancy are usually assumed to require lifelong insulin treatment. The striking finding was not just that patients could stop insulin, but in every case, the overall blood sugar was lower without patients having problems with too low blood sugar," said Dr. Ewan Pearson, the lead author of one of the studies who did the work while he was at the Peninsula Medical School in Exeter, England.

Pearson, now a clinician scientist at the University of Dundee in Scotland, added that these findings aren't just applicable to babies being diagnosed right now, but to anyone who was diagnosed with neonatal diabetes. In Pearson's study, they even had a 36-year old who'd been diagnosed with diabetes in infancy respond to treatment with sulfonylureas, which are older medications commonly used to treat type 2 diabetes because they stimulate the production of insulin.

"For those rare people affected by neonatal diabetes mellitus, this is a miracle," said Dr. Mark Sperling, author of an accompanying editorial in the journal and a pediatrics professor at Children's Hospital of Pittsburgh and the University of Pittsburgh, Pa.

Sperling added that neonatal diabetes probably affects about one in 100,000 people. To be considered neonatal diabetes, the disease must occur within the first six months of life, according to Pearson.

Each of the studies looked at the effect of sulfonylureas on people diagnosed with neonatal diabetes that had certain genetic mutations.

In Pearson's study, it was 49 people in England, France and Norway who had defects in a gene called Kir6.2. In the other study, led by Dr. Andrey Babenko and Dr. Michel Polak, there were 34 French patients with mutations in the gene ABCC8, which affects a sulfonylurea receptor known as SUR1.

These mutations affect the way potassium moves through the beta cells in the pancreas. When humans eat, the energy from the food is translated into electrical signals, and potassium helps that signal move through the beta cells, according to Sperling. When the beta cells receive this information, they begin to produce insulin to help the body process blood sugar.

In people who have mutations in the genes that allow potassium to move through the beta cells, this important communication is disrupted.

"The beta cell is sleeping, like Sleeping Beauty, and nobody knows that she is there; nobody even recalls that she is there," said Polak, head of pediatric endocrinology at Hopital Necker Enfants Malades in Paris. "The prince -- the sulfonylureas -- kiss her and wake her (the beta cells) up."

"The beauty of the story is that with an old and well-known drug, a sulfonylurea, we can restore the beta cell function and stop insulin in children and adults with the mutation, because we understood that it was accurate to use it there [due to] pharmacogenomics," said Polak.

It's important to note, however, that these findings have no bearing on the more common form of insulin-dependent diabetes.

"Unfortunately, [this] does not apply to autoimmune diabetes, as the beta cells are destroyed [in that type]," said Polak.

And, not everyone with neonatal diabetes was able to get off insulin. In each study, five people didn't respond to the treatment, suggesting that for some, there may be a window of opportunity where this treatment will be effective.

Additionally, Sperling pointed out that while neonatal diabetes is rare, it's possible that some people with type 2 diabetes could have these mutations, and therefore would be helped by sulfonylurea treatment.

"There may be a subtype of type 2 where these would be specifically of use," said Sperling.

"This study has very important therapeutic implications for all patients who were diagnosed with diabetes before the age of six months," said Pearson of his study. "We would urge all such patients to contact their health care professional for consideration of genetic testing, as over half are likely to be able to successfully transfer off insulin injections."

More information

To learn more about diabetes and children, visit the National Institutes of Health.

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