Spinocerebellar ataxia 3 (SCA3) is an autosomal dominant disorder caused by an abnormal CAG expansion mutation in the ATXN3 gene, and the most frequent SCA worldwide.
We report the cases of two women with a heterozygous CAG expansion in the ATXN3 gene (patient 1, 76 CAG repeats; patient 2 with 75 CAG repeats) who have been treated in our outpatient clinic. Their clinical phenotype is remarkable mainly for global ataxia, pyramidal syndrome (mainly on the lower limbs), limb dystonia, and hypokinesia (Video, patient 1, segment 1). Symptoms appeared at 18 years of age in patient 1, and 30 years of age in patient 2.
Noteworthily, the patients also had eyelid opening apraxia associated with asymmetrical blepharospasm (Video, patient 1, segment 2; patient 2). These findings have already been described in SCA3 and SCA2 patients [1, 2]; however, video documentation is hard to find. There is a wide phenotypical overlap between all hereditary dominant ataxias, and particular clinical features may be helpful during the diagnostic workup. Ocular findings may be of major importance to narrow the diagnostic possibilities. Most reviews focus on abnormalities of supranuclear eye movements. For instance, saccadic pursuit, rebound nystagmus, and ophthalmoparesis (mainly vertical), which are prevalent in SCA3 cases . However, both eyelid opening apraxia and blepharospasm seem to receive less attention in most reviews; nonetheless, these appear to be additional clinical findings that points toward both SCA3 and SCA2.
This report aims to draw attention to eyelid opening apraxia and blepharospasm during the neurological examination, and to serve as a source of teaching material to illustrate SCA3’s phenotypical nuances.
Written informed consent was obtained per institute guidelines for videotaping the subjects and publishing their video and history. We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this work is consistent with those guidelines.
The authors thank the patient and family for their kind cooperation during the study.
The authors have no competing interests to declare.
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