Brussels, 09 Aug 2006
Research breakthroughs could revolutionise treatment for sufferers of neonatal diabetes, many of whom could swap their insulin injections for tablets.
Neonatal diabetes affects an estimated 1 in 100,000 newborns. It is characterised by hyperglycaemia (abnormally high blood sugar levels) during the first days or months of life, and is treated with insulin injections. In some cases patients require treatment for their entire life. Other patients may experience a remission of the condition between the ages of one week and one month, only for the disease to return later in life.
Two pieces of research, both of which are published in the latest edition of the New England Journal of Medicine, shed new light on the causes of neonatal diabetes and show how drugs called sulphamides could be at least as effective as insulin at controlling this rare form of diabetes. Sulphamides are oral anti-diabetic drugs that increase the secretion of insulin and so lead to a better regulation of blood sugar levels.
A Franco-American team looked at the gene coding for the sulphamide receptor in a number of children with neonatal diabetes that could not be explained by known genetic anomalies. Nine of these were found to have mutations in the gene for the sulphamide receptor SUR1.
Sulphamides block potassium channels in the beta cells of the pancreas, which are involved in insulin secretion. When the sulphamide receptor is defective, the potassium channels remain open and block the secretion of insulin. However, the defective channels remain sensitive to sulphamides, opening up the possibility of treating these children with sulphamides instead of insulin. According to the paper, treatment with sulphonylurea successfully restored the children's blood sugar levels to normal.
The second study, lead by the Peninsula Medical School in the UK, focused on patients who had neonatal diabetes as a result of a mutation in the Kir6.2 gene, which is also involved in the potassium channel that controls insulin secretion. The study found that treatment with sulphonylurea tablets allowed 90 per cent of patients who were diagnosed in their first six months of life to stop injecting insulin.
The patients involved ranged in age from 3 months to 36 years, and the treatment has already been shown to work for up to two years. Furthermore, patients who switched to the new tablets actually improved their control over the disease.
'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,' commented Dr Ewan Pearson of the University of Dundee. 'It is rare to find such an excellent response to any treatment.'
'This research shows that genetics really do make a difference - knowing the cause of this diabetes helped us know what type of tablet might work,' added Professor Andrew Hattersley of the Peninsula Medical School. 'What we want now is to test more people who were diagnosed before they were six months old to see if their treatment can be successfully altered.'
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