paroxysmal tonic upgaze

Eye Movement Disorders with CACNA1A Mutations

Clinical Characteristics
Ocular Features: 

Eye movement disorders secondary to CACNA1A mutations include congenital nystagmus, abnormal saccades and paroxysmal tonic upgaze and can be early indicators of underlying neurologic disease.  The median age of presentation in one series was 1.2 years.

Systemic Features: 

Eye movement disorders form a group of conditions that may occur in isolation but can also be associated with underlying neurological disease (vida infra).

Genetics

Heterozygous mutations in the CACNA1A gene (19p13.13) have been associated with a number of conditions including type 2 episodic ataxia (108500), familial hemiplegic migraine 1 (141500), and 2 (602481), spinocerebellar ataxia 6 (183086), and several types of eye movement disorders including congenital nystagmus, abnormal saccades, and paroxysmal tonic upgaze. 

The gene product is a transmembrane pore-forming subunit of a voltage-gated calcium channel expressed abundantly in neuronal tissue.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

The use of calcium channel blockers may have some benefit in preventing severe hemiplegic migraine.

References
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