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

Familial hemiplegic migraine


Other Names:
FHM; Hemiplegic Migraine, Familial; Hemiplegic-ophthalmoplegic migraine
Categories:
This disease is grouped under:
Familial hemiplegic migraine (FHM) is an inherited form of hemiplegic migraine. Hemiplegic migraine is a type of migraine with aura that causes motor impairment (such as weakness) in addition to at least one visual, sensory, or speech disturbance (aura) that occurs before the migraine headache begins.[1][2] FHM commonly begins during childhood or adolescence.[2] The symptoms of FHM can be scary and distressing.[1]

FHM is currently classified into 4 subtypes, distinguished by their genetic cause:[1][2]
  • FHM type 1 (the most common type) is caused by mutations in the CACNA1A gene and is commonly associated with cerebellar degeneration.
  • FHM type 2 is caused by mutations in the ATP1A2 gene and may be associated with seizures.
  • FHM type 3 is caused by mutations in the SCN1A gene.
  • FHM type 4 is diagnosed if no mutation currently known to cause FHM can be identified.
Inheritance of FHM is autosomal dominant, but not everyone who inherits a mutation responsible for FHM will have symptoms (a phenomenon called reduced penetrance).[1][3] The diagnosis of FHM requires that at least one first- or second-degree relative has also been diagnosed with hemiplegic migraine. Tests such as a CT scan or MRI of the brain, cerebrospinal fluid analysis, and EEG may be needed to rule out other potential causes of headache and neurological symptoms.[1] Genetic testing may confirm the subtype of FHM in a family. Treatment of hemiplegic migraine involves medications to alleviate pain, stop the migraines, and prevent future migraines. Severe headache attacks may require hospitalization.[1] In most people with hemiplegic migraines, aura symptoms completely go away in between migraines and the migraines become less frequent with age.[2] Rarely, hemiplegic migraines may cause permanent neurological symptoms, cognitive impairment, stroke, coma, or death.[1][2]

Last updated: 1/2/2019
Familial hemiplegic migraine (FHM) commonly begins during childhood or adolescence.[2] It is characterized by migraine with aura along with motor impairment (such as weakness on one side of the body, known as hemiparesis), in addition to “classic” aura which is marked by visual, sensory, and/or speech disturbances. The aura usually occurs before the migraine headache begins, developing over minutes and lasting less than an hour.[1][2] Motor symptoms such as weakness may switch sides between or during attacks, and rarely may affect both sides of the body.[1] While a headache doesn’t always follow, when it does, it causes throbbing pain, nausea, and/or sensitivity to light. The headache can last several hours to a few days[2][3] The symptoms of FHM can be scary and distressing.[1]
Last updated: 1/2/2019

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.

Showing of 8 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormality of movement
Movement disorder
Unusual movement
[ more ] 		0100022
Hemiplegia/hemiparesis
Paralysis or weakness of one side of body
0004374
30%-79% of people have these symptoms
Ataxia 0001251
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
5%-29% of people have these symptoms
Dysphasia 0002357
EEG abnormality 0002353
Pigmentary retinopathy 0000580
Sensorineural hearing impairment 0000407
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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.
  • Orphanet lists international laboratories offering diagnostic testing for this condition.
There are no official treatment guidelines for familial hemiplegic migraine (FHM), and no randomized, controlled trials regarding treatment for hemiplegic migraine have been conducted.[4] People with hemiplegic migraine typically are treated with the same medicines used for typical migraine with aura (for pain, and to stop or prevent migraines). However, medicines that constrict the blood vessels (vasoconstrictors) should be avoided because they may increase the risk for stroke.[1][2][4] Examples of vasoconstrictors that may be used to treat typical migraine with aura include triptans and ergotamines.[1] Treatment may depend on the severity and frequency of attacks as well as specific symptoms, and therefore may vary from person to person. Multiple therapies, either alone or in combination, may need to be tried before finding a treatment regime that is helpful.

Treatment of sudden hemiplegic migraine “attacks” aims to ease symptoms and may include the use of non-steroidal anti-inflammatory drugs (NSAIDs), anti-nausea medicines (antiemetics), and/or prescription pain medicines.[1][2][5] A medicine called ketamine, ingested through the nose (intranasal), may shorten the duration of aura symptoms if taken as soon as symptoms begin.[1][5][6]

Examples of medicines that may be used to prevent attacks (prophylactic medicines) may include verapamil, flunarizine, ketamine, lamotrigine, and naloxone. Non-randomized studies have suggested acetazolamide may be effective in preventing attacks in some people with FHM.[1][2][4] Other medicines that may be used to prevent attacks include amitriptyline, topiramate, and valproic acid.[1][2] Individualized anti-seizure therapy may additionally be needed for people with FHM who have seizures (particularly those with FHM type 2).[2]
Last updated: 1/2/2019

Management Guidelines

  • Orphanet Emergency Guidelines is an article which is expert-authored and peer-reviewed that is intended to guide health care professionals in emergency situations involving this condition.  
Although most people with familial hemiplegic migraine (FHM) recover completely between episodes, neurological symptoms such as memory loss and problems with attention can last for weeks or months. The occurrence of FHM attacks tends to decrease with age. The eventual neurologic outcome is often benign; however, about 20 percent of individuals with FHM develop mild but permanent difficulty coordinating movements (ataxia), which may worsen with time, and nystagmus (rapid, involuntary eye movements). Unusually severe migraine episodes have been reported in some people with FHM. These episodes may include fever, seizures, prolonged weakness, coma, and, rarely, death.[2][3]
Last updated: 11/28/2016

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

  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 

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

Social Networking Websites

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

  • Genetics Home Reference (GHR) contains information on Familial hemiplegic migraine. This website is maintained by the National Library of Medicine.
  • The Migraine Trust, a support organization, offers information on Familial hemiplegic migraine

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • 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 Familial hemiplegic migraine. 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. Submit a new question

  • What is the prognosis for memory retention when patient is on prophylactic medications such a Topamax? The migraines are interfering with my work, yet the Topamax makes me fuzzy as well. Will that resolve? See answer


  1. Kumar A, Arora R. Headache, Migraine Hemiplegic. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; October, 2018; https://www.ncbi.nlm.nih.gov/books/NBK513302/.
  2. Jen JC. Familial hemiplegic migraine. GeneReviews. May 14, 2015; https://www.ncbi.nlm.nih.gov/books/NBK1388/.
  3. Familial hemiplegic migraine. Genetics Home Reference (GHR). January, 2014; https://ghr.nlm.nih.gov/condition/familial-hemiplegic-migraine.
  4. Robertson CE. Hemiplegic migraine. UpToDate. Waltham, MA: UpToDate; 2018; https://www.uptodate.com/contents/hemiplegic-migraine.
  5. Hemiplegic Migraine. American Migraine Foundation. https://americanmigrainefoundation.org/resource-library/hemiplegic-migraine/. Accessed 12/7/2018.
  6. Kaube H, Herzog J, Käufer T, Dichgans M, Diener HC. Aura in some patients with familial hemiplegic migraine can be stopped by intranasal ketamine. Neurology. 2000; 55(1):139. https://n.neurology.org/content/55/1/139.long.