Diabetes Mellitus

Diabetes mellitus is a serious hormonal disease in which body cells fail to absorb glucose from the blood. This disease occurs when there is not enough insulin in the blood or when the body cells do not respond normally to blood insulin. In either case, the cells cannot obtain enough glucose from the blood, and thus starved for fuel, they are forced to burn the body's supply of fats and proteins. The complications due to diabetes include severe dehydration, cardiovascular and kidney disease, nerve damage and gangrene.

Types of Diabetes

There are two types of diabetes mellitus.

Type 1

It is insulin dependent diabetes mellitus (IDDM). It is also called juvenile diabetes as it usually occurs in early age before 40, even before the age of 15. It is an autoimmune disease, in which white blood cells (T cells) of the body's own immune system attack and destroy the pancreatic β cells. Sometimes special viral infection activate autoimmune response. As a result, the pancreas does not produce enough insulin and glucose build up in the blood. Patient require regular supplement of insulin, and most take the hormone by direct injection.

Genetic basis of Type 1

The insulin gene is located on the short arm of chromosome number 11 (eleven). Polymorphism and genetic variation within this locus is responsible for diabetes type 1 susceptibility. Today it is a multifactorial (polygenic with environmental influence) inheritance associated with several alleles.

Type 2

It is called non-insulin dependent diabetes mellitus and found in 76% to 80% of diabetic patient. It develops even though the pancreatic (3 cells are functioning normally and there is plenty of insulin in the blood. Type II diabetes occurs because the body cells fail to respond adequately to insulin. The disease seems to be inherited and may result from genes that code for malfunctioned insulin receptors on the cells. Type II diabetes accounts for 90% cases. It is almost always associated with obesity and often does not show up until a person is over 40. The disease is managed by controlling sugar intake and by exercising and dieting to reduce weight, recommended diet are high insoluble fiber and low in fat and sodium.

Genetic Basis of Type 2

The genetic component is the form of an underlying tendency to develop diabetes under certain environmental conditions. About 2-5 percent of type II diabetics get the disease early in life, before 25 years of age. It is called maturity onset diabetes of the young (MODY). It can be inherited as an autosomal dominant trait. About 50% of the disease are caused by mutation in glucokinase gene. Glucokinase enzyme usually converts glucose to glucose 6 phosphate in pancreas. MODY can also be caused by mutation in any of the four genes which encode transcription factors involved in pancreatic development and insulin regulation, but the four genes do not play any significant role in adult - onset type 2.