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Genetic and Rare Diseases Information Center (GARD)

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Hemiplegic migraine


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Cause

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What causes hemiplegic migraine?

There are two types of hemiplegic migraine (HM), which are distinguished based on the family history in affected people: familial hemiplegic migraine (FHM, in which at least one other close family member has the condition) and sporadic hemiplegic migraine (SHM, in which there is no family history).[1]

FHM may be caused by changes (mutations) in the CACNA1A, ATP1A2, SCN1A, and PRRT2 genes. The first three of these genes give the body instructions for making proteins involved in moving charged atoms (ions) across cell membranes. This process is important for for normal signaling between nerve cells (neurons) in the brain and other parts of the nervous system. Researchers think that mutations in these genes may upset the balance of ions in neurons, affecting the release and uptake of certain neurotransmitters in the brain. The exact function of the PRRT2 gene is not yet understood but is also thought to play a part in controlling signals between neurons. When the genes involved in FHM do not work correctly, the signaling abnormalities between neurons lead to the development of severe headaches and auras in affected people.[2] The genetic cause in many families with FHM remains unknown.[3]

While SHM occurs in people with no history of the condition in their family, most cases are due to new (de novo) mutations that occur for the first time in the affected person. Some people with SHM do inherit a mutation from a parent who has the mutation but is not affected. The ATP1A2 and CACNA1A genes have been found to cause SHM in addition to FHM. Many people with SHM do not have a mutation in one of these genes; however, researchers think that mutations in other, unidentified genes are also involved in the condition.[4]
Last updated: 11/18/2014

References
  1. Anne Ducros. Familial or sporadic hemiplegic migraine. Orphanet. April, 2008; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=569. Accessed 11/17/2014.
  2. Familial hemiplegic migraine. Genetics Home Reference. January, 2014; http://ghr.nlm.nih.gov/condition/familial-hemiplegic-migraine. Accessed 11/18/2014.
  3. Jen JC. Familial Hemiplegic Migraine. GeneReviews. September 2009; http://www.ncbi.nlm.nih.gov/books/NBK1388/#fhm.Clinical_Description.
  4. Sporadic hemiplegic migraine. Genetics Home Reference. February, 2014; http://ghr.nlm.nih.gov/condition/sporadic-hemiplegic-migraine. Accessed 11/18/2014.


See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.