Researchers pinpoint new MS genes
Two genes linked to multiple sclerosis (MS) have been identified by researchers in three major international studies. This is the first time in 30 years that genes associated with the debilitating disease have been uncovered. MS is a chronic disease of the central nervous system. It is estimated that the disease affects more than 1 in 1,000 people in most Western countries. The first signs of the onset of MS are loss of balance, reduced vision and bouts of localised paralysis. Eventually, patients may become totally paralysed and wheelchair-bound. Susceptibility to MS is known to be strongly influenced by genetic factors. Between 1972 and 1975 researchers found that a variant of the human leukocyte antigen (HLA-DRB1) gene increases the likelihood of getting the disease up to fourfold. Since then however, very little progress has been made in identifying the other genes thought to be instrumental in developing the disease. Now researchers from the UK, US and Sweden have pinpointed two further genes that play a role in MS. The first was identified by researchers who examined variants of three genes suspected to be linked to the disease. Four large cohorts from the US, the UK and Belgium were used, totalling 10,000 people. The researchers found that variants in one of these genes - IL7R-alpha - were consistently more common in the patients with MS than the healthy control subjects. Their finding was confirmed by researchers in a separate study, who examined a large group of people from Denmark, Finland, Norway and Sweden, and observed a similar association between IL7R-alpha and the risk of MS. Both studies were published in the journal Nature Genetics. The researchers estimate that the IL7R-alpha gene can increase the risk of developing MS by between 20% and 30%. The other gene, known as IL2R, was identified in a third study, published in the New England Journal of Medicine. Here researchers conducted a genome-wide association scan on some 12,000 subjects. Both of the newly-identified genes make proteins that act as receiving 'antennae' for interleukins, molecules which help control the activity of immune system cells. IL2R-alpha has also been implicated in two other autoimmune diseases, type 1 diabetes and autoimmune thyroid disease. Although the findings are unlikely to lead immediately to new tests or treatments (since as many as 100 genes are thought to play a role in MS), researchers say that the genes will help them better understand the mechanisms that trigger the disease. They also hope their findings will pave the way for the discovery of other MS susceptible genes.
Countries
Sweden, United Kingdom, United States