Researchers believe that multiple sclerosis may in part be inherited. First-, second-, and third-degree relatives of people with MS have an increased risk of developing the disease. Siblings of an affected person have a 2%-5% risk of developing MS themselves.
Researchers believe that there is more than one gene that makes a person more likely to get MS. Some scientists theorize that MS develops because a person is born with a genetic predisposition to react to some environmental agent, which, upon exposure, triggers an autoimmune response.
Sophisticated new techniques for identifying genes may help answer questions about the role of genetics in the development of MS.