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Migraine, familial hemiplegic, 3(FHM3)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonym: Migraine, Familial Hemiplegic, 3
Gene (location): SCN1A (2q24.3)
Monarch Initiative: MONDO:0012320
OMIM®: 609634

Disease characteristics

Excerpted from the GeneReview: Familial Hemiplegic Migraine
Familial hemiplegic migraine (FHM) falls within the category of migraine with aura. In migraine with aura (including FHM) the neurologic symptoms of aura are unequivocally localizable to the cerebral cortex or brain stem and include visual disturbance (most common), sensory loss (e.g., numbness or paresthesias of the face or an extremity), and dysphasia (difficulty with speech). FHM must include motor involvement, such as hemiparesis (weakness of an extremity). Hemiparesis occurs with at least one other symptom during FHM aura. Neurologic deficits with FHM attacks can be prolonged for hours to days and may outlast the associated migrainous headache. FHM is often earlier in onset than typical migraine, frequently beginning in the first or second decade; the frequency of attacks tends to decrease with age. Approximately 40%-50% of families with CACNA1A-FHM have cerebellar signs ranging from nystagmus to progressive, usually late-onset mild ataxia. [from GeneReviews]
Joanna C Jen   view full author information

Additional descriptions

Familial hemiplegic migraine-3 (FHM3) is a severe subtype of migraine with aura characterized by some degree of hemiparesis during the attacks (Dichgans et al., 2005). For a general phenotypic description and a discussion of genetic heterogeneity of FHM, see FHM1 (141500).  http://www.omim.org/entry/609634
From MedlinePlus Genetics
Unusually severe migraine episodes have been reported in some people with familial hemiplegic migraine. These episodes have included fever, seizures, prolonged weakness, coma, and, rarely, death. Although most people with familial hemiplegic migraine recover completely between episodes, neurological symptoms such as memory loss and problems with attention can last for weeks or months. About 20 percent of people with this condition develop mild but permanent difficulty coordinating movements (ataxia), which may worsen with time, and rapid, involuntary eye movements called nystagmus.

In some types of migraine, including familial hemiplegic migraine, a pattern of neurological symptoms called an aura precedes the headache. The most common symptoms associated with an aura are temporary visual changes such as blind spots (scotomas), flashing lights, zig-zagging lines, and double vision. In people with familial hemiplegic migraine, auras are also characterized by temporary numbness or weakness, often affecting one side of the body (hemiparesis). Additional features of an aura can include difficulty with speech, confusion, and drowsiness. An aura typically develops gradually over a few minutes and lasts about an hour.

Familial hemiplegic migraine is a form of migraine headache that runs in families. Migraines usually cause intense, throbbing pain in one area of the head, often accompanied by nausea, vomiting, and extreme sensitivity to light and sound. These recurrent headaches typically begin in childhood or adolescence and can be triggered by certain foods, emotional stress, and minor head trauma. Each headache may last from a few hours to a few days.  https://medlineplus.gov/genetics/condition/familial-hemiplegic-migraine

Clinical features

From HPO
MedGen UID:
Concept ID:
Loss of strength in the arm, leg, and sometimes face on one side of the body. Hemiplegia refers to a complete loss of strength, whereas hemiparesis refers to an incomplete loss of strength.
MedGen UID:
Concept ID:
Sign or Symptom
Paralysis (complete loss of muscle function) in the arm, leg, and in some cases the face on one side of the body.
MedGen UID:
Concept ID:
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
MedGen UID:
Concept ID:
Sign or Symptom
Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light.
Migraine with aura
MedGen UID:
Concept ID:
Disease or Syndrome
A type of migraine in which there is an aura characterized by focal neurological phenomena that usually proceed, but may accompany or occur in the absence of, the headache. The symptoms of an aura may include fully reversible visual, sensory, and speech symptoms but not motor weakness. Visual symptoms may include flickering lights, spots and lines and/or loss of vision and/or unilateral sensory symptoms such as paresthesias or numbness. At least one of the symptoms of an aura develops gradually over 5 or more minutes and/or different symptoms occur in succession.
MedGen UID:
Concept ID:
Mental or Behavioral Dysfunction
An abnormally heightened sensitivity to loud sounds.
MedGen UID:
Concept ID:
Disease or Syndrome
Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation.

Professional guidelines


Rao PV, Lu X, Pattee P, Turner M, Nandgaonkar S, Paturi BT, Roberts CT Jr, Nagalla SR
J Assoc Physicians India 2005 Jun;53:521-6. PMID: 16121806


Orphanet, Hemiplegic Migraine (HM), 2013

Recent clinical studies


Barbieri R, Bertelli S, Pusch M, Gavazzo P
J Headache Pain 2019 Nov 15;20(1):107. doi: 10.1186/s10194-019-1056-2. PMID: 31730442Free PMC Article
Domitrz I, Kosiorek M, Żekanowski C, Kamińska A
Hum Genomics 2016 Jan 8;10:3. doi: 10.1186/s40246-015-0057-8. PMID: 26747084Free PMC Article

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