Ocular motility in genetically defined autosomal dominant cerebellar ataxia.
OBJECTIVE
To describe ocular motility in patients having genetically characterized dominant cerebellar ataxia.


METHODS
Observational case series.


METHODS
Nine ataxic adults having the following molecular genetic diagnoses underwent ophthalmic examination and ocular motility recordings: four with spinocerebellar ataxia type 6 (SCA-6), three with SCA-3, one with SCA-1, and one with episodic ataxia type 2 (EA-2).


RESULTS
Versions were normal in eight patients. Most were orthotropic, but one with SCA-3 had exotropia at near. The near point of convergence was remote in five patients. Eight of nine patients had horizontal nystagmus evoked by lateral gaze. All patients with SCA-6 had downbeat nystagmus. Downbeat nystagmus was absent in SCA-1, SCA-3, and EA-2. Three patients with SCA-6 and one with EA-2 had symptomatic improvement when treated with acetazolamide.


CONCLUSIONS
Patients with genetically defined dominant cerebellar ataxia generally had normal binocular alignment and versions and only mild vergence impairment. Downbeat nystagmus was strongly associated with the SCA-6 mutation, whose associated episodes of dizziness and imbalance may be relieved by acetazolamide.
Durig
Jacques S
JS
Department of Ophthalmology, University of California, Los Angeles, California 90095-7002, USA.
Jen
Joanna C
JC
Demer
Joseph L
JL
D000086:Acetazolamide / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D004247:DNA / Q000032:analysis; D004585:Electrooculography; D005133:Eye Movements; D005260:Female; D005799:Genes, Dominant; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D016133:Polymerase Chain Reaction; D020754:Spinocerebellar Ataxias / Q000150:complications* / Q000188:drug therapy / Q000235:genetics*
D004247:DNA; D000086:Acetazolamide