Multiple sclerosis, or MS, is a lifelong
autoimmune disorder that can cause severe disability. An autoimmune
disorder is one in which the body produces antibodies that attack its own
tissue. People with MS produce antibodies that attack the white matter in the
brain and spinal cord.
What is going on in the body?
In multiple sclerosis, the myelin, or coating of nerve fibers, becomes
inflamed in the brain and spinal cord. The inflammation damages the myelin, and
signals cannot be passed along to
About 70% of the individuals with MS have what is called the
relapsing-remitting, or RR type, of MS. They have periodic relapses, or
episodes where symptoms worsen. These relapses are followed by remissions,
which involve partial or full relief from symptoms. The remaining 30% of people
with MS have chronic, progressive disease. Although there are several
subgroups, most individuals with chronic, progressive disease have a disease
course that worsens steadily over time.
What are the causes and risks of the disease?
The cause of multiple sclerosis is not known. There are four major scientific
theories about the cause of MS:
Environmental. Worldwide, MS seems to be more common around the 40th
parallel in the Northern and Southern hemispheres and is more prevalent in
northern Europe. A person who is born in one of these areas but moves to
another area before adolescence has a lower risk of developing MS.
Genetic. Having a parent or sibling with MS significantly increases a
person's risk of MS.
Immunologic. It is generally accepted that multiple sclerosis is an
Viral. It is possible that a viral infection can trigger MS.
Some neurologists believe that MS develops because a person is
born with a genetic predisposition to react to an environmental agent. When
that person comes into contact with the agent, the contact
triggers an autoimmune response that causes MS.