CausesBy Mayo Clinic staff
The exact cause of type 1 diabetes is unknown. Scientists do know that in most people with type 1 diabetes, the body's own immune system — which normally fights harmful bacteria and viruses — mistakenly destroys the insulin-producing (islet) cells in the pancreas. Genetics may play a role in this process, and exposure to certain viruses may trigger the disease.
Insulin key to sugar entering cells
Whatever the cause, once the islet cells are destroyed, your child will produce little or no insulin. Normally, the hormone insulin helps glucose enter your child's cells to provide energy to the muscles and tissues. Insulin comes from the pancreas, a gland located just behind the stomach. When everything is working properly, once you eat, the pancreas secretes more insulin into the bloodstream. As insulin circulates, it acts like a key by unlocking microscopic doors that allow sugar to enter the body's cells. Insulin lowers the amount of sugar in the bloodstream, and as the blood sugar level drops, so does the secretion of insulin from the pancreas.
The liver acts as a glucose storage and manufacturing center. When insulin levels are low — when you haven't eaten in a while, for example — the liver releases stored glycogen, which is then converted to glucose to keep your blood glucose level within a normal range.
Dangerous sugar level in bloodstream
In type 1 diabetes, none of this occurs because there's no or very little insulin to let glucose into the cells. So instead of being transported into your child's cells, sugar builds up in your child's bloodstream, where it can cause life-threatening complications.
The cause of type 1 diabetes is different from the more common type 2 diabetes. In type 2, the islet cells are still functioning, but the body becomes resistant to insulin or the pancreas doesn't produce enough insulin.
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