Migraine, familial hemiplegic, 3(FHM3)

MedGen UID:: 400655
•Concept ID:: C1864987
•: Disease or Syndrome

Synonym:	Migraine, Familial Hemiplegic, 3

Gene (location): Gene(s) directly associated with this condition or phenotype.	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]

Authors:
Joanna C Jen view full author information

Additional descriptions

From OMIM
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
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.

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. https://medlineplus.gov/genetics/condition/familial-hemiplegic-migraine

Clinical features

From HPO

Hemiparesis

MedGen UID:: 6783
•Concept ID:: C0018989
•: Finding

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.

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Hemiplegia

MedGen UID:: 9196
•Concept ID:: C0018991
•: 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.

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Seizure

MedGen UID:: 20693
•Concept ID:: C0036572
•: 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.

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Photophobia

MedGen UID:: 43220
•Concept ID:: C0085636
•: Sign or Symptom

Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light.

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Migraine with aura

MedGen UID:: 57822
•Concept ID:: C0154723
•: 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.

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Phonophobia

MedGen UID:: 155864
•Concept ID:: C0751466
•: Mental or Behavioral Dysfunction

An abnormally heightened sensitivity to loud sounds.

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Blindness

MedGen UID:: 99138
•Concept ID:: C0456909
•: 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.

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