National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

West syndrome

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Other Names:
Infantile spasm; IS; X-linked infantile spasm syndrome; Infantile spasm; IS; X-linked infantile spasm syndrome; X-linked infantile spasms; West's syndrome; Tonic spasms with clustering, arrest of psychomotor development and hypsarrhythmia on EEG See More
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West syndrome is characterized by a specific type of seizure (infantile spasms) seen in infancy and childhood. This syndrome leads to developmental regression and causes a specific pattern, known as hypsarrhythmia (chaotic brain waves), on electroencephalography (EEG) testing. The infantile spasms usually begin in the first year of life, typically between 4-8 months. The seizures primarily consist of a sudden bending forward of the body with stiffening of the arms and legs; some children arch their backs as they extend their arms and legs. Spasms tend to occur upon awakening or after feeding, and often occur in clusters of up to 100 spasms at a time. Infants may have dozens of clusters and several hundred spasms per day. Infantile spasms usually stop by age five, but may be replaced by other types of seizures.[1] Many disorders leading to brain injury, such as birth problems, cerebral anomalies, metabolic disorders, and genetic disorders can lead to these spasms, making it important to identify the underlying cause. [2][3] In some children, no cause can be found.[1] The goals of treatment are to reduce or eliminate seizures, and include several medications, such as corticoids, avigabatrin, and antiepileptic drugs.[2] Some children have spasms as the result of brain lesions, and surgical removal of these lesions may result in improvement.[1]
Last updated: 6/9/2017

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.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Developmental regression
Loss of developmental milestones
Mental deterioration in childhood
[ more ] 		0002376
Hypsarrhythmia 0002521
Infantile spasms 0012469
Myoclonus 0001336
30%-79% of people have these symptoms
Abnormality of skin morphology
Abnormal skin structure
0011121
Percent of people who have these symptoms is not available through HPO
Choreoathetosis 0001266
Dyskinesia
Disorder of involuntary muscle movements
0100660
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty
[ more ] 		0002015
Dyspnea
Trouble breathing
0002094
Dystonia 0001332
Epileptic encephalopathy 0200134
Generalized myoclonic seizure 0002123
Hyperreflexia
Increased reflexes
0001347
Hypertonia 0001276
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] 		0000252
Muscular hypotonia of the trunk
Low muscle tone in trunk
0008936
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
Ventriculomegaly 0002119
X-linked recessive inheritance 0001419
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Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.

Management Guidelines

  • The NORD Physician Guide for West syndrome was developed as a free service of the National Organization for Rare Disorders (NORD) and it's medical advisors.  The guides provide a resource for clinicians about specific rare disorders to facilitate diagnosis and treatment of their patients with this condition. 

FDA-Approved Treatments

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.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

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
The differential diagnosis may be problematic and should include Sandifier syndrome, benign myoclonus, hyperekplexia (see these terms), gastro-oesophageal reflux and breath holding spells.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to West syndrome. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

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.

Organizations Supporting this Disease

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.

Where to Start

In-Depth Information

  • 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.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • 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 West syndrome. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. National Institutes of Health. Infantile Spasms Information Page. National Institute of Neurological Disorders and Stroke. February 22, 2011; http://www.ninds.nih.gov/disorders/infantilespasms/infantilespasms.htm. Accessed 3/21/2011.
  2. Glaucer TA. Infantile Spasm (West Syndrome). Medscape Reference. October 16, 2014; http://emedicine.medscape.com/article/1176431-overview#a5.
  3. West syndrome. Orphanet. March, 2007; http://www.orpha.net/consor/cgi-bin/Disease_Search.php?lng=EN&data_id=894.