GTR Home > Conditions/Phenotypes > Familial hemiplegic migraine type 1

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 familial hemiplegic migraine) 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, i.e., 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 FHM1 have cerebellar signs ranging from nystagmus to progressive, usually late-onset mild ataxia. Cerebral infarction and death have rarely been associated with hemiplegic migraine.

Associated genes

  • Also known as: APCA, BI, CACNL1A4, CAV2.1, EA2, FHM, HPCA, MHP, MHP1, SCA6, CACNA1A
    Summary: calcium channel, voltage-dependent, P/Q type, alpha 1A subunit

Clinical features

  • Drowsiness
  • Fever
  • Hemianopic blurring of vision
  • Seizure
  • Anxiety
  • Confusion
  • Nystagmus
  • Tremor
  • Psychosis
  • Agitation
  • Ataxia
  • Coma
  • Hemiparesis
  • Cerebellar atrophy
  • Migraine with aura
  • Hemiplegia
  • Dysphasia
  • Visual hallucinations
  • Dyscalculia
  • Auditory hallucinations
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