Friday, May 14, 1999 Published at 16:24 GMT 17:24 UK
Diabetes vaccine hope
Patients with type 1 depend on daily insulin injections
A vaccine for diabetes could be on the horizon after scientists announced they had found a gene that could be responsible for causing the incurable condition.
The finding applies to type 1 - or insulin-dependent - diabetes.
Sufferers cannot produce the hormone insulin, which is needed to control blood sugar levels. Without it, death is inevitable and patients need an insulin injection every day.
Now scientists believe they have found the gene that kills the body's insulin-producing cells.
Children are most affected
Type 1 diabetes is also known as juvenile diabetes, because most sufferers develop it during childhood or adolescence.
Until now, nobody knew what caused the disease, although some thought it might be inherited.
If doctors confirm the gene they have identified - the GAD gene - is responsible for the disease, they could work on treatments to prevent it developing.
Dr Ji-Won Yoon, lead author of the research, said: "We found that if we suppress GAD expression in the pancreatic cells, then we can prevent diabetes.
"It is that simple."
Immune system destroys cells
Dr Yoon and colleagues from the University of Calgary in Alberta, Canada performed the research and published their findings on Friday in the journal Science.
They found that when the GAD gene was active it caused cells to create a protein called glutamic acid decarboxylase.
When the immune system detected the protein, it attacked it as if it were a foreign substance. In doing so, it also destroyed the cells in the pancreas that produce insulin.
The result is type 1 diabetes.
But in experiments with mice bred to be diabetic, Dr Yoon's team managed to switch off the GAD gene, with the result that they remained free of diabetes.
Dr Yoon said his study suggests it may be possible to prevent type 1 diabetes with a vaccine that makes the immune system ignore the GAD gene.
"If you inject GAD then the T-cell will learn to tolerate GAD and will not attack the beta cells (which make insulin)," he said.
"The concept is that you inject GAD into young children then they would not get diabetes. That is prevention."
'Move towards prevention'
Dr Robert Goldstein, medical director of the US Juvenile Diabetes Foundation, said Yoon's discovery was a "very important step" toward, perhaps, developing a diabetes vaccine.
"This approach has the promise of modulating the autoimmune response and going toward prevention," he said.
He did warn, however, that many more basic questions had to be answered before such a vaccine could be produced.
It is estimated that world wide there are 135 million people with diabetes. Of these, about 10% have type 1 diabetes, the rest have type 2.
Type 2 - or non-insulin dependent - diabetes is the most common form of the disease. It usually occurs in people who are over the age of 45 and overweight.
Type 2 sufferers do not make enough insulin, or are unable to make proper use of it, but the condition can be controlled through exercise and diet.