One of the biggest studies ever undertaken into multiple sclerosis has identified 29 new genetic factors that are implicated in the development of the disease.
The nature of the genes that have been linked with MS has demonstrated with a high degree of certainty that the root causes of the illness can be traced to the faulty functioning of the body's immune system, scientists said.
Nearly 10,000 individuals with multiple sclerosis took part in the study and their genomes were scanned to find the genetic differences with the DNA of over 17,000 healthy people. The total number of genetic faults linked with the disease now amounts to 57.
Alastair Compston, of the University of Cambridge, one of the lead authors of the study published in Nature, said there have been rival theories about what are the important factors implicated in triggering the disease, one of the most common neurological conditions affecting young adults.
"Our research settles a long-standing debate on what happens first in the complex sequences of events that leads to disability in multiple sclerosis," he said. "This has important implications for future treatment strategies. It puts immunology right at the front end of the disease, absolutely."
The study involved a relatively new technique called genome-wide scanning, which involves analysing the entire length of a patient's DNA for anomalies that appear not to exist in healthy people and could therefore be linked with the disease. Previous research had established that multiple sclerosis has a strong genetic component.
Some of the newly identified genes are known to be involved in the immune system and some have also been linked with other auto-immune diseases, where the immune defences start to attack the body's own cells and tissues, said Professor Peter Donnelly of Oxford University, who was involved in the research.
In a parallel study, American scientists have identified a similar array of genes involved in multiple sclerosis, which the researchers said could open the way to new drugs and treatments.
"We have known for some time that many devastating diseases of the immune system must have common genetic causes. Now we have an outline of a map that tells us where we can look for common treatments," said Chris Cotsapas of Yale University.