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Genetic and Rare Diseases Information Center (GARD)

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Lambert Eaton myasthenic syndrome

Other Names for this Disease
  • Eaton Lambert syndrome
  • Lambert Eaton syndrome
  • LEMS
  • Myasthenic syndrome of Lambert-Eaton
  • Myasthenic-Myopathic syndrome of Lambert-Eaton
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Your Question

My husband had Lambert Eaton myasthenic syndrome. Are our two children at risk to develop this condition?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is Lambert Eaton myasthenic syndrome?

Lambert Eaton myasthenic syndrome (LEMS) is a disorder of the neuromuscular junction. The neuromuscular junction is the site where nerve cells meet muscle cells and help activate the muscles.[1] This syndrome occurs when antibodies interfere with electrical impulses between the nerve and muscle cells. It may be associated with other autoimmune diseases, or more commonly coincide with or precede a diagnosis of cancer such as small cell lung cancer. Symptoms may include muscle weakness, a tingling sensation in the affected areas, fatigue, and dry mouth.[1] Treatment of a underlying disorder or cancer is the first priority of treatment.
Last updated: 4/22/2011

What causes Lambert Eaton myasthenic syndrome?

Lambert Eaton myasthenic syndrome is the result of an autoimmune process which causes a disruption of electrical impulses between nerve cells and muscle fibers.[2][3][4] In cases where Lambert Eaton myasthenic syndrome appears in association with cancer, the cause may be that the body’s attempt to fight the cancer inadvertently causes it to attack nerve fiber endings, especially the voltage-gated calcium channels found there. The trigger for the cases not associated with cancer is unknown.[2][5]
Last updated: 10/28/2009

Is Lambert Eaton myasthenic syndrome genetic?

The answer to this question is complex. Lambert Eaton myasthenic syndrome is an autoimmune condition which means that the immune system, which normally protects the body from foreign invaders (infections, cancers, etc.) mistakenly attacks the body's own tissues. Lambert Eaton myasthenic syndrome is frequently associated with other known autoimmune disease such as pernicious anemia, thyroid disease, and Sjögren's syndrome. A family history of autoimmune disease is found in 34% of patients who have this primary diagnosis.[6] 

While the condition is not known to follow a specific pattern of inheritance, there appears to be a genetic predisposition to autoimmune diseases in general.[5] Families with a history of Lambert Eaton myasthenic syndrome may benefit from consulting with a genetics professional. 

Last updated: 10/28/2009

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:  

  • GeneTests has a searchable directory of US and international genetics and prenatal diagnosis clinics.
  • The National Society of Genetic Counselors provides a searchable directory of US and international genetic counseling services.
  • The American College of Medical Genetics has a searchable database of US genetics clinics.  
  • The American Society of Human Genetics maintains a database of its members, which includes individuals who live outside of the United States. Visit the link to obtain a list of the geneticists in your country, some of whom may be researchers that do not provide medical care.
Last updated: 12/13/2012