Lambert Eaton myasthenic syndrome
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
Age of Onset
Autosomal dominant ?A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease
Autosomal recessive ?Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype
X-linked dominant ?X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
X-linked recessive ?Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder
Mitochondrial or multigenic ?Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.
Multigenic or multifactor ?Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.
Other Names (AKA)
LEMS; Eaton Lambert syndrome; Lambert Eaton syndrome;
Musculoskeletal Diseases; Nervous System Diseases
Lambert Eaton myasthenic
Muscle weakness may vary in severity and can lead to:
- Difficulty climbing stairs
- Difficulty lifting objects
- Need to use hands to arise from sitting or lying positions
- Difficulty talking
- Difficulty chewing
- Drooping head
- Swallowing difficulty, gagging, or choking
Vision issues may additionally occur including:
- Blurry vision
- Double vision
- Difficulty maintaining a steady gaze
Other symptoms may include blood pressure changes, dizziness upon rising, and dry mouth.
This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
|Medical Terms||Other Names||
|80%-99% of people have these symptoms|
|EMG: decremental response of compound muscle action potential to repetitive nerve stimulation||0003403|
|EMG: repetitive nerve stimulation abnormality||0030000|
|Progressive proximal muscle weakness||0009073|
|Reduced tendon reflexes||0001315|
Dry mouth syndrome
[ more ]
|30%-79% of people have these symptoms|
Difficulty getting a full erection
Difficulty getting an erection
[ more ]
|5%-29% of people have these symptoms|
Decreased ability to sweat
[ more ]
|Orthostatic hypotension due to autonomic dysfunction||0004926|
In instances where LEMS is associated with
Medications and therapies that may be used to treat Lambert-Eaton myasthenic
The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.
- Amifampridine phosphate(Brand name: Firdapse) Manufactured by Catalyst Pharmaceuticals, Inc.
FDA-approved indication: November 2018, amifampridine phosphate (Fridapse) was approved for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults.
National Library of Medicine Drug Information Portal
Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.
Conditions with similar signs and symptoms from Orphanet
In 60% of LEMS patients, a different diagnosis was initially made such as myasthenia gravis (MG), inclusion body myositis, Guillain-Barré syndrome (GBS), amyotrophic lateral sclerosis (ALS) (see these terms), lumbar canal stenosis, early-phase Parkinson's disease and lower body parkinsonism.
Visit the Orphanet disease page for more information.
Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
American Autoimmune Related Diseases Association (AARDA)
19176 Hall Road, Suite 130
Clinton Township, MI 48038
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
- MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
- The Merck Manuals Online Medical Library provides information on this condition for patients and caregivers.
- Muscular Dystrophy Association has information and resources about Lambert Eaton myasthenic syndrome. Please click on the link to access this resource.
- The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
- The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
- Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
- The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
- Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
- PubMed is a searchable database of medical literature and lists journal articles that discuss Lambert Eaton myasthenic syndrome. Click on the link to view a sample search on this topic.
- NINDS Lambert-Eaton Myasthenic Syndrome Information Page. Institute of Neurological Disorders and Stroke (NINDS). https://www.ninds.nih.gov/Disorders/All-Disorders/Lambert-Eaton-Myasthenic-Syndrome-Information-Page#disorders-r1. Accessed 12/22/2016.
- Stickler, DE. Lambert-Eaton Myasthenic Syndrome. Medscape. May 06, 2016; https://emedicine.medscape.com/article/1170810-overview.
- Lambert-Eaton Syndrome. MedlinePlus. 5/30/2016; https://www.nlm.nih.gov/medlineplus/ency/article/000710.htm.
- Titulaer, M. Lambert-Eaton myasthenic syndrome. Orphanet. November 2013; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=43393.
- Lambert-Eaton Myasthenic Syndrome (LES). Muscular Dystrophy Association (MDA). https://www.mda.org/disease/lambert-eaton-myasthenic-syndrome. Accessed 12/22/2016.
- Gozzard, P. Lambert-Eaton myasthenic syndrome. NORD. 2012; https://rarediseases.org/rare-diseases/lambert-eaton-myasthenic-syndrome/.