Oculomotor and visual axis systems sparing in spinocerebellar ataxia type 13 R420H

Abstract

This study aimed to examine a Filipino kindred harboring the spinocerebellar ataxia type 13 (SCA13)R420H mutation to investigate phenotypic features that may assist in differentiating this disease from other SCAs. Forty-one members of a 3-generation Filipino kindred segregating the KCNC3R420H allele were comprehensively examined. Of these individuals, 21 were affected and 20 were unaffected. The affected individuals ranged in age from 10 to 82 years old. This examination included assessments for gaze-evoked horizontal/vertical nystagmus, slow/hypometric/hypermetric saccades, fragmented smooth pursuit, square wave jerks on fixation, horizontal/vertical ophthalmoplegia, diplopia, abnormal visual acuity, and optic nerve atrophy. The 20 unaffected individuals in this pedigree demonstrated no clinical signs of oculomotor abnormalities. Two patients did demonstrate slight delay in initiation of ballistic saccades, 1 showing increased eyeblink during this delay. This finding is of unclear significance as none of the other affected individuals, including the most severe, exhibited this finding. (PsycINFO Database Record (c) 2016 APA, all rights reserved)