What is the role of genetics in the etiology of migraine-associated vertigo?

Updated: Jan 18, 2019
  • Author: Aaron G Benson, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Answer

The genetic cause of a rare type of migraine has been discovered. Familial hemiplegic migraine, a form of migraine with aura, is associated with mutations in the CACNA1A gene located on chromosome arm 19p13. [16] This gene codes for a neuronal calcium channel. Defects involving this gene are also involved in other autosomal dominant disorders that have neurologic symptoms (see Table 1, below). One example is that of episodic ataxia type 2 (EA2), which is also known as periodic vestibulocerebellar ataxia and acetazolamide-responsive hereditary paroxysmal cerebellar ataxia. In cases of EA2, a pH abnormality has been discovered, and it often resolves with medication (eg, acetazolamide, valproic acid, calcium channel blocker).

Table 1. CACNA1A Gene Defects Associated With Autosomal Dominant Disorders With Neurologic Symptoms (Open Table in a new window)

GENE Defect

Syndrome

Symptoms and Signs

Point mutation

Familial hemiplegic migraine

Episodic hemiparesis for 60min or less, followed by headache; gaze-evoked and downbeat nystagmus may persist after spells

Point mutation

Episodic ataxia type 2 (EA2)

Episodic ataxia and vertigo, gaze-evoked and downbeat nystagmus, abnormal pursuit on electronystagmography (ENG)

CAG repeats

Spinocerebellar ataxia type 6 (SCA6)

Progressive ataxia, gaze-evoked and downbeat nystagmus, abnormal pursuit on ENG

Adapted from Tusa, 1999. [17]


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