It is actually called Multiple Sclerosis, not multiplex sclerosis.
Multiple sclerosis (MS) is a chronic, potentially debilitating disease that affects your central nervous system, which is made up of your brain and spinal cord. Multiple sclerosis is widely believed to be an autoimmune disease, a condition in which your immune system attacks components of your body as if they're foreign.
In multiple sclerosis, the body mistakenly directs antibodies and white blood cells against proteins in the myelin sheath, a fatty substance that insulates nerve fibers in your brain and spinal cord. This results in inflammation and injury to the sheath and ultimately to the nerves that it surrounds. The result may be multiple areas of scarring (sclerosis). Eventually, this damage can slow or block the nerve signals that control muscle coordination, strength, sensation and vision.
Multiple sclerosis affects an estimated 300,000 people in the United States and probably more than 1 million people around the world — including twice as many women as men. Most people experience their first signs or symptoms between ages 20 and 40.
Multiple sclerosis is unpredictable and varies in severity. In some people, multiple sclerosis is a mild illness, but it can lead to permanent disability in others. Treatments can modify the course of the disease and relieve symptoms.
These factors may increase your risk of developing multiple sclerosis:
* Heredity. Multiple sclerosis is more common in people of Northern European descent. There also appears to be a genetic component to the condition, although the risk to children of people affected by MS is less than 5 percent over their lifetime. Researchers suspect that the tendency to develop multiple sclerosis is inherited, but the disease manifests only when environmental triggers are present.
* Environmental factors. Environmental factors have some influence on multiple sclerosis. Many viruses and bacteria have been suspected of causing MS, most recently the Epstein-Barr virus, known also for causing infectious mononucleosis. Some studies have suggested that developing infection at a critical period of exposure may lead to conditions conducive to the development of MS a decade or more later.
* Geographical factors. Multiple sclerosis is more common in countries with temperate climates, including Europe, southern Canada, northern United States, and southeastern Australia. The reason is unknown.
So, there is a chance your boyfriend can get it or his children. The signs and symptoms vary depending on the location of the nerves involved.