[Subclinical eye movements as an indicator for inheritance of congenital nystagmus and central nervous system disease].

Clinically unaffected relatives of families with a history of either inherited congenital nystagmus or inherited neurogenic muscular and cerebellar atrophy underwent electrooculographic examination under three distinct test conditions. We found an increase in the number of square wave jerks, a higher than normal intensity score (defined in terms of frequency X amplitude of an involuntary saccade, unit: o/s) and nystagmus as compared with 110 normal individuals ranging in age from 21 to 89 years. These findings suggest a possible autosomal dominant mode of inheritance in the case study of congenital nystagmus presented. The results show abnormal eye movements in some family members from a family with inherited cerebellar degeneration with acquired nystagmus, suggesting that these family members are affected with the disorder. This study documents the rarely described observation of a connection between inherited cerebellar degeneration with inherited distal neurogenic muscular atrophy.