A Juvenile Disease with Lasting Effects

Juvenile is defined as youthful, and diabetes (in Greek diabetes means 'running through') is a disease that is named for the excessive urination that results if inflicted with this disorder. Juvenile diabetes is a disease that attacks one in three hundred youths before the age of twenty. These are very high numbers and so Dr. L. Field of the Canadian Genetic Diseases Network at the University of Calgary is trying to get to the root of the problem. Her strategy is to use a field of study called Genetics which is named after segments of DNA (deoxyribonucleic acid) called genes (unit of hereditary information). Genes specify the kinds of proteins that are made by cells. By studying DNA, Dr. Field has found two new genes that, if present, play an important role in the development of this disease.

Diabetes is a disease that is ultimately caused by a malfunction of the machinery needed to transport the most important fuel, glucose, across your cell membranes. Glucose is needed to supply your body with the energy required to run a marathon or just to sit and think. This deficiency in glucose uptake leaves a large excess of glucose in the blood that is eventually excreted via the urine. Why can't the cell transport glucose across its membrane? In order to transport glucose across the cell membrane, a specific protein called insulin is needed. Insulin acts by stimulating glucose receptors within its target cells, to bind to the surface and carry glucose across the cell membrane. Without these receptors, glucose cannot enter a cell and as a result cannot be utilized by the body. There are different causes for inadequate glucose utilization associated with different types of diabetes. In a person with juvenile diabetes, glucose is not utilized because the necessary cells in the pancreas that produce insulin are destroyed by the body's own defense mechanisms (an autoimmune disease).

Juvenile diabetes results from a contribution of many genes, which makes the puzzle far more difficult to piece together. However, after a lot of hard work, the genes were identified using a 'genome (all DNA within an individual) screen' to identify 100 'marker' genes in families that have two or more diabetic children. These marker genes were then amplified by the polymerase chain reaction (PCR). PCR is a technique used to create many, many copies of the gene in question so that it can be studied with greater ease at higher concentrations. Eventually, two genes on chromosome (condensed form of DNA and nuclear proteins) 11 and 15 were found to be partially responsible for the onset of juvenile diabetes.

At this time, the only treatment for a person with this disease is to inject insulin on a daily basis. However, now that the genes that cause a person to be susceptible to juvenile diabetes have been discovered, this may eventually lead to its early detection and then treatment before the disease has an opportunity to affect the individual at risk.