Diabetes interferes with the body's ability to store energy from food. The pancreas makes a substance called insulin that helps with this energy storage. Type 1 diabetes, also called juvenile diabetes because it is usually diagnosed before adulthood, occurs when the pancreas stops making insulin. The result is high blood sugar levels. Over time, high blood sugar levels can lead to blindness, kidney failure, nerve damage, and heart disease. Fortunately, good care with diet; exercise; and medications to control blood sugar level, blood pressure, and cholesterol level helps to prevent these complications. People with type 1 diabetes develop an abnormal immune reaction that causes the body to make substances called autoantibodies, which attack the insulin-producing cells (called islet cells) in the pancreas. There are several different types of autoantibodies, which are called islet cell autoantibodies. People whose first-degree relatives (parents, siblings, or children) have type 1 diabetes are at greater risk for the disease than people without a family history. An important concern of people with type 1 diabetes is whether their children will also develop the disease. Measuring autoantibodies might be useful in predicting who will develop diabetes.