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What is Amyotrophic lateral sclerosis (ALS)?

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, reports almost 16,000 people in the United States have ALS as of 2014; every year doctors tell about 5,000 people that they have it. 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 slightly 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 prevalence of ALS for 2014, 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.

Is ALS linked to the environment?

Health studies have not found definite environmental factors that are linked with either ALS or other MNDs. Some studies suggested a possible link with exposure to heavy metals (e.g., lead and mercury). Other studies suggested a link with exposure to trace elements, solvents, radiation, and agricultural chemicals. No confirmed link was found with infections, diet, physical activity, and injury.

Is ALS equally common among men and women?

ALS is slightly more common in men than women, but recent studies suggest that this difference is decreasing over time. Familial ALS is equally common in men and women.

Is ALS related to age?

ALS is age related; most people with ALS find out they have it when they are between 55 and 75 years of age

How long do people with ALS live?

Most people live from 3 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.

Can ALS be inherited?

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. These cases are caused by several inherited factors. The most common is in a gene called SOD1.

Is familial ALS equally common among men and women?

Familial ALS is found equally among men and women.

How long do people with familial ALS live?

People with familial ALS usually do not fare as well as a person with ALS who are not related, and typically live only one to two years after symptoms appear.

Do clusters of ALS possibly exist? (I have been told by the doctor that I have ALS. Several other people from my town/school/ community/neighborhood have also been told by their doctor that they have ALS. Could these cases of ALS all be related?)

It is unknown whether clusters of ALS exist. Although it is possible that cases of ALS are related, studying clusters does not help when trying to determine what factors cause or trigger ALS. While ATSDR does not specifically conduct cluster investigations, suspected clusters of the disease have made it possible to conduct activities to identify the number of ALS cases in selected areas and the possible related environmental factors.

What are the problems with studying possible clusters of ALS?

The cause of most cases of ALS is unknown so we don’t know what to look for in a person’s past.We do not have current or complete data on the number of people with ALS. As a result, we cannot determine the “normal” or “expected” number of cases among a group of people or in a specific area. The expected number of cases of a disease is often found in an existing disease registry, as with cancer. However, there are no registries or ongoing tracking efforts for ALS in the United States.The small number of cases in a possible cluster limits the ability to tell the difference between the number of cases that would occur naturally by chance and a number of cases that is greater than would be expected. Studies with large numbers of people are needed to determine the causes of such a disease.

What are motor neuron (nerve cell) diseases?

ALS is one of a group of conditions known as motor neuron diseases (MNDs). ALS affects nerve cells for muscles of both the upper and lower body. ALS accounts for 85 percent of MND cases. Other MNDs affect nerve cells for muscles of either the upper or lower body. Other MNDs include progressive muscular atrophy, progressive bulbar palsy, and primary lateral sclerosis.

What is MND prognosis?

Eighty-five percent of people with an MND have ALS. Most persons who are first diagnosed with progressive muscular atrophy, progressive bulbar palsy, or primary lateral sclerosis will develop problems with nerve cells for both upper and lower body muscles. The person will then be told they have ALS.

Where can I get more information about ALS?

Please visit our Resource Links page for other ALS related websites.

Where can I find information on clinical trials?

The National ALS Registry recruits for clinical trials and epidemiological studies. In addition, the National Institutes of Health, a government agency, has a list of clinical trials. Go to the “Clinical Trials” web site to find a list of federally and privately supported clinical trials in the United States and around the world. ClinicalTrials.gov gives you information about a trial’s purpose, who may take part, locations, and phone numbers for more details. Use the ALS Clinical Trials web site for clinical trials specifically related to ALS.

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