Blinding Brothers: Spinocerbellar Ataxia Presenting as Cone Rod Dystrophy

Author: Erika Jean Salvame (Philippines)

Co-authors: Jocelyn Sy, Manuel Benjamin Ibanez IV, Elyse Dorothy Anselmo, Kristine Pormida, Godard Artajos

Purpose

To present a case of cone rod dystrophy as an initial manifestation of spinocerebellar ataxia in 2 brothers.

Setting/Venue

Single Center Tertiary Hospital in the Philippines

Methods

Case Report

Results

A 21 year old male consulted for a 5 year history of bilateral progressive blurring of vision described as worsening ability to read. No comorbidities were noted but patient eventually also developed body weakness and decreased motor and speech skills.Best corrected visual acuity is 20/200 on the right eye and 20/160 on the left with bilateral tritan and deutan defects on Farnsworth D15. Posterior pole showed granular hypopigmentation consistent with bull’s eye pattern in both eyes that was seen as a ring of granular hyperautofluorescence in fundus autofluorescence. Fluorescein angiography showed window defects at the center of the macula and macular optical coherence tomography showed thinning and loss of photoreceptors more concentrated foveally. ERG had attenuated a and b wave. Neurologic examination shows dysmetria and gait disorder while the neuroimaging was unremarkable. Family history showed strong history of progressive bilateral blurring of vision, eventually developing speech and balance disorder, with onset occurring 20 years younger in every generation. Diagnosis was spinocerebellar ataxia and patient underwent genetic counseling, physical , occupational and low vision therapy. His accompanying brother was also screened and was noted to have cone-rod macular dystrophy, with mild unilateral dysmetria.

Conlusions

Spinocerebellar ataxia is a rare hereditary disease with autosomal dominant penetration. Its common ocular manifestation include eye movement disorders but a variant may also associated with retinal dystrophy. This case highlights the importance in the recognition of the association between cone rod dystrophy and spinocerebellar ataxia. This is particularly of value since spinocerebellar ataxia is correlated to have genetic anticipation, wherein the next generation may have an earlier and more severe onset of the disease. The diagnosis of spinocerebellar ataxia due to the presenting cone rod dystrophy in one brother was crucial in diagnosis the early manifestation of the same disease in his sibling. While no definitive management is currently available. Early therapy may delay progression of the debilitating sequelae of the disease.

Financial Disclosure

Department of Health Eye Center- East Avenue Medical Center, Philippines: Ongoing Vitreo Retina Fellowship