Episodic ataxia type 2: an uncommon inherited CNS channelopathies.

The author reports the first Thai patient with a rare inherited ataxic disorder characterized by intermittent episodes of ataxia, headache and vertigo. The patient was well between attacks despite persistent nystagmus on examination. Magnetic resonance imaging of the brain revealed cerebellar atrophy. All symptoms were ameliorated by acetazolamide therapy. This clinical syndrome was previously described as acetazolamide-responsive episodic ataxia which was subsequently shown to be associated with mutations in a alpha1A-subunit of P/Q type voltage-gated calcium channel gene, known as 'episodic ataxia type 2'. Clinical and molecular aspects of episodic ataxia type 2 were also reviewed.