Emily Malcolm, PhD avatar

by Emily Malcolm, PhD |

Share this article:

Share article via email

A diagnosis of Lambert-Eaton myasthenic syndrome (LEMS) often leaves patients and their families with a plethora of questions. Reliable information can be scarce for rare diseases, whether it’s a matter of where to go for news, treatment options and concerns, or how to come in contact with other patients.

Below are some of the FAQs about LEMS.

What is LEMS?

LEMS is a rare autoimmune disease, meaning it’s caused by the immune system going awry, attacking and damaging nerve cell endings, leading to muscle weakness.

More information can be found on our “What is LEMS” page.

How do I know if I have LEMS?

LEMS causes muscle weakness in the arms and legs, which progresses gradually over weeks or months to other areas, such as the face and the throat. The presence of these symptoms does not automatically mean a person has LEMS. Tests of muscles and their responses are typically taken, as are blood tests to identify autoantibodies, or antibodies against the body’s own tissues.

About half of all LEMS cases are associated with a particular cancer called small cell lung cancer. In these patients, muscle weakness may progress more rapidly.

Most patients are 35 or older at the onset of symptoms.

Read more on our “LEMS Symptoms” and “LEMS Diagnosis” pages.

We also have more information on small cell lung cancer.

How prevalent is LEMS?

LEMS is a rare disease. The National Organization for Rare Disorders estimates that there are about 400 cases in the U.S., with a worldwide incidence of 2.8 cases reported per 1 million people. LEMS is usually more common among men than women, for reasons that are not yet known.

Read about patient stories and experiences in our forums, and in the column “LEMme Tell Ya” written by Dawn DeBois, one of our contributors with LEMS.

Is LEMS contagious?

No, LEMS is not contagious.

Can LEMS be inherited?

No genetic cause has been identified for LEMS, but genetics may play a role in how likely a person is to develop an autoimmune disease.

Where can I find out more about treatments and research?

Some information on treatment options is available on our “LEMS Treatment” page. We also regularly publish articles on our website that cover a range of news of relevance to LEMS, including ongoing research and potential treatments in development.

The following organizations also offer information about treatments and ongoing research in LEMS:


Last updated: July 17, 2019


Lambert-Eaton News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.