Pathogenesis of clinical signs in recessive ataxia with saccadic intrusions.
We describe a family of Slovenian descent with progressive ataxia, corticospinal signs, axonal sensorimotor neuropathy, and disruption of visual fixation by saccadic intrusions. Chromosome mapping indicated a mutation on 1p36, and this recessive disorder has been designated spinocerebellar ataxia with saccadic intrusions. Affected patients showed overshooting horizontal saccades, macrosaccadic oscillations, and increased velocity of larger saccades; other eye movements were normal. Slowed conduction in axons that are selectively vulnerable to the molecular defect could explain both the sensorimotor neuropathy and the saccadic disorder, which would be caused by delayed feedback control because of slow conduction in cerebellar parallel fibers.
Swartz
Barbara E
BE
Department of Neurology, Veterans Affairs Medical Center, and University Hospitals, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106-5040, USA.
Li
Sheng
S
Bespalova
Irina
I
Burmeister
Margit
M
Dulaney
Eugene
E
Robinson
Farrel R
FR
Leigh
R John
RJ
D000328:Adult; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D016001:Confidence Intervals; D005260:Female; D005808:Genes, Recessive; D006801:Humans; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000150:complications / Q000235:genetics* / Q000473:pathology; D013132:Spinocerebellar Degenerations / Q000150:complications / Q000235:genetics* / Q000473:pathology