Studies point to new genes associated with MS risk

The studies, conducted by teams of scientists working all over the world, will help shed light on the causes of multiple sclerosis (MS) according to the researchers.

Both studies involved scanning DNA samples from more than 20,000 MS patients and unaffected individuals in the US and Europe, and looking for single nucleotide polymorphisms (SNPs), which are single-letter variations in a gene’s DNA code. Published simultaneously in the New England Journal of Medicine and Nature Genetics, the studies demonstrate an association between MS and SNPs in two genes that encode interleukin receptors, proteins that serve as antennae on the surface of immune cells.

MS typically causes limb weakness, vision loss and problems with coordination, and is the most common disabling neurological disorder of young adults. Although scientists believe there is a genetic link in the cause of the disease, most of the genes responsible remain unidentified. In the mid-1970s, researchers discovered that human leukocyte antigens (HLA) account for some of this genetic susceptibility.

However, HLA does not fully explain the genetic basis of MS; scientists have long realized that other genes must play a role that has been difficult to detect. Some studies have pointed to other HLA genes, but neither of the two genes reported today belong to that category. Both genes encode receptors on the surface of T cells – the immune system’s mobile infantry – that enable the cells to respond to regulatory, secreted proteins called interleukins.

“These are the first non-HLA genes to be unequivocally associated with MS,” said Dr Pericak-Vance, one of the scientists involved in the study. “They give us a new way of looking at the biology of the disease, and could be targets for therapeutic development.”