What is ALS?

Many people know ALS as Lou Gehrig’s disease, named after the famous baseball player who got the illness and had to retire in 1939 because of it. ALS is a disease that affects the nerve cells that make muscles work in both the upper and lower parts of the body. This disease makes the nerve cells stop working and die. The nerves lose the ability to trigger specific muscles, which causes the muscles to become weak and leads to paralysis.

How many people have ALS?

Although no one knows for sure, as of 2017 we estimate there are over 31,000 patients living with ALS in the United States. On average 5,000 new patients are diagnosed every year with this disease. Because records on ALS have not been kept throughout the country, it is hard to estimate the number of ALS cases in the United States. ALS is more common in men than women. ALS is age related; most people find out they have it when they are between 55 and 75 years of age, and live from 2 to 5 years after symptoms develop. How long a person lives with ALS seems to be related to age; people who are younger when the illness starts live slightly longer. To read the latest national incidence and prevalence estimates, please click here.

About 5–10% of ALS cases occur within families. This is called familial ALS and it means that two or more people in a family have ALS. Familial ALS is found equally among men and women. People with familial ALS usually do not fare as well as persons with ALS who are not related, and typically live only one to two years after symptoms appear.

What causes ALS?

No one knows what causes most cases of ALS. Scientists have been studying many factors that could be linked with ALS such as heredity and environmental exposures. Other scientists have looked at diet or injury. Although no cause has been found for most cases of ALS, a number of inherited factors have been found to cause familial ALS. In the future, scientists may find that many factors together cause ALS.