As of 2015, the exact cause of juvenile diabetes remains unknown, although genetics may be a contributing factor, reports the Mayo Clinic. Juvenile diabetes is currently called type 1 diabetes, states the American Diabetes Association. This disease leads to the immune system destroying the cells that produce insulin in the pancreas, notes the Mayo Clinic.
The cells in the pancreas that create insulin are called islet cells. Once enough of them have been killed, the body produces only a small amount of insulin, if any. Insulin reduces the levels of sugar within the bloodstream. The more sugar levels drop, the less insulin the pancreas continues to send into the bloodstream, according to the Mayo Clinic.
While keeping sugar levels at a reasonable level is important, some sugar is vital for cellular activity. The two primary sources of sugar are dietary intake and the liver. Insulin helps the sugar make its way into the cells and power activities. The liver stores some excess sugar in the form of glycogen, and when sugar levels drop, the liver turns the glycogen it has stores into sugar to maintain levels. However, type 1 diabetics have no insulin to send the sugar into the cells, so it aggregates in the bloodstream, reports the Mayo Clinic.