TUESDAY, Oct. 1 (HealthDay News) -- An international team of scientists has identified 48 new genetic variants associated with multiple sclerosis (MS), a new study says.

The findings bring to 110 the number of genetic variants linked to MS and offer new insight into the biology of the progressive neurological disease.

The genes pinpointed in the new study underline the central role played by the immune system in the development of MS and show significant overlap with genes known to be involved in other autoimmune diseases, according to the study, which was published online Sept. 29 in the journal Nature Genetics.

The International Multiple Sclerosis Genetics Consortium included 193 investigators in 13 countries. They analyzed DNA from more than 29,000 people with MS and nearly 51,000 people without the disease, making it the largest MS study ever undertaken.

Although there are now 110 genetic variants known to be associated with MS, each variant individually confers only a small risk of developing the disease. Collectively, these genetic variants explain about 20 percent of the genetic component of MS, the researchers said.

The new findings are "a major step forward," according to study co-leader Jacob McCauley of the University of Miami Miller School of Medicine.

"Describing the genetic underpinnings of any complex disease is a complicated but critical step. By further refining the genetic landscape of multiple sclerosis and identifying novel genetic associations, we are closer to being able to identify the cellular and molecular processes responsible for MS and therefore the specific biological targets for future drug treatment strategies," he said in a University of Miami news release.

MS affects more than 2.5 million people worldwide, according to the news release. It causes inflammation and damage to the central nervous system that leads to problems with mobility, balance, sensation and thinking, depending upon where the damage occurs.

The risk of developing MS is higher among people who have a family history of the disease. Research in twins and adopted people has suggested that this increased risk is primarily due to genetic factors.

More information

The American Academy of Family Physicians has more about multiple sclerosis.