Diabetes mellitus is caused by a deficiency in the secretion or action of insulin. Nearly six percent of the United States population shows some degree of abnormality in glucose metabolism indicative of diabetes or a tendency toward the condition. Diabetes mellitus is a group of diseases in which the regulatory activity of insulin is defective. There are two major clinical classes of the disease. There's type I, which is insulin-dependent diabetes mellitus (IDDM), and type II, which is non-insulin dependent diabetes mellitus (NIDDM). IDDM begins early in life and quickly becomes severe. NIDDM is slow to develop, milder, and often goes unrecognized. IDDM requires insulin therapy and careful, lifelong control of the balance between glucose intake and insulin dose. Characteristic symptoms of diabetes are excessive thirst (polydipsia) and frequent urination (polyuria), leading to intake of large volumes of water. Also, excessive hunger and food consumption (polyphagia). These changes are due to excretion of large amounts of glucose in the urine. The term diabetes mellitus means "excessive excretion of sweet urine." Suspected genes that cause IDDM are localized on many chromosomes, showing that type I diabetes is a multigene autoimmune response. Some investigators believe the immune system is confused. They think that the pancreatic beta cells could be recognized as an alien entity because of previous exposure to a foreign substance that had similar proteins to the beta cells. It's believed that T cells target and enzyme glutamate decarboxylase (GAD) present in the beta cells. GAD coverts the amino acid glutamate into - aminobutyric acid (GABA), a messenger between neurons. GAD is located in the brain hidden from the immune system. Investigators are hinting that the immune system may not recognize it as a self-protein. GAD resembles the (p69) protein that beta cells show when they are infected by viruses. GAD ...
