Throughout the last three decades, scientists have tried to ferret out genetic links if any that might lead to multiple sclerosis. Because the disease affects relatively young people in the age group of 20 to 40 years, researchers have evinced interest in finding gene variants linked to MS.

Now researchers from the Duke University's Center for Human Genetics report finding a gene variant on chromosome 5 that is thus far only the second genetic risk factor identified in over three decades for multiple sclerosis.

Reporting in the July 29 online issue of Nature Genetics and in the New England Journal of Medicine, researchers confirmed that this was the biggest step taken in the identification of a causal relationship between MS and genetic variants.

The central nervous system consists of the brain, the spinal cord and the optic nerves. A substance called the myelin protects the nerve fibers from shock and also helps in conducting electric impulses from the brain to other parts of the body. This myelin sheath is made up of fatty tissue and can be considered as a shock absorber.

In multiple sclerosis, it is this myelin sheath that is damaged. The areas of the nerves that lose myelin have sclerosis or scar tissue left behind that severely impairs the ability of the nerves to transmit electric signals to the rest of the body.

The earlier impression was the damage caused to myelin was the work of the body's own immune system. However in the three years from 1972 and 1975, researchers had identified a variant of the human leukocyte antigen (HLA-DRB1) as quadrupling the risk of developing MS. This gene present on chromosome 6 was the only variant linked to MS for the last three decades and was involved in the regulation of immune function. This strengthened the perception of MS being an autoimmune issue.

The present findings assume added significance in the light of this fact. Margaret Pericak-Vance, co-senior author of the current paper said the genetics behind MS was a continuing puzzle.

Researchers analyzed genetic information from 12,360 people using a technique called genomic convergence. This group included both MS patients as well as healthy ones. Researchers homed in on interleukin 7 receptor (IL7R) alpha chain gene as being involved with increasing MS risk.

This particular gene is also involved with the normal functioning of the immune system. Researchers of the NEJM paper used a genome-wide approach to scan for the presence of MS risk genes. This technique looked at the entire genome for possible genes involved in causing multiple sclerosis.

Lead author of the NEJM paper, Dr. David Hafler of Harvard Medical School, said the finding of additional genes implicated in MS would act as a blueprint for new therapies for the condition. These new genetic findings hold out hope for over 400,000 MS patients in the United States and over 2.5 million worldwide.

The symptoms of multiple sclerosis vary from person to person. Some patients might experience loss of balance and muscle coordination, which makes walking increasingly difficult, while others might experience varied symptoms like slurred speech, tremors, stiffness, and bladder problems.

The issue with MS is there is no cure for this debilitating condition. Although the Food and Drug Administration has approved certain drugs like natalizumab (Tysabri) to treat advanced and chronic symptoms of MS, there is no permanent or stable treatment for the same.

The identification of new MS risk genes might herald a new era in the treatment of this condition, which is one of the worst diseases known to man.

Dr. John Richert, executive vice president for research and clinical programs at the National Multiple Sclerosis Society said the identification of the new genes will be able to initiate several new therapies direct at these particular genes and would give short-term relief to multiple sclerosis patients.