Cherry Red Spot Myoclonus Syndrome

ABSTRACT

Cherry red spot is a known sign of retinal occlusive disease. However, when it occurs bilaterally in a young patient with neurological findings, a diagnosis of retinal occlusive disease becomes farfetched, and the possibility of a storage disorder is raised. We report multimodal retinal imaging findings in a case of cherry-red spot myoclonus syndrome. This form of imaging helps in the ophthalmological diagnosis and management of these patients.

The cherry red spot is a sign of retinal ischaemia. However, when it occurs bilaterally in a young patient with neurological findings, storage disorders must be searched for. We herein present multimodal retinal imaging findings of a patient with cherry red spot myoclonus syndrome. Cherry red spot myoclonus syndrome is a presentation of storage diseases like Niemann-Pick, Tay-Sachs, Sandhoff, Fabry, Gaucher diseases and sialidosis.¹

This photo essay presents the findings in a 14-year-old boy who had confirmed sialidosis type I and cherry red spot myoclonus syndrome. He was seen in the Ophthalmology department due to progressive visual loss and ataxia. On examination, his best-corrected visual acuity was 20/200 OU. Except for punctate cataract in both eyes, the anterior segment examination was unremarkable. Funduscopy demonstrated bilateral cherry red spots with healthy optic discs (Figure 1). Infrared autofluorescence fundus imaging (IRAF) revealed a hypoautofluorescent pattern of the parafoveal area with sparing of the fovea (Figure 2). The blue autofluorescence (BAF) study showed a hyperautofluorescent area encircling the fovea (Figure 3) in accordance with the hyporeflective area on IRAF. Fluorescein angiography (FA) demonstrated normal vasculature with hypofluorescence of the parafoveal area (Figure 4). Optical coherence tomography showed hyperreflectance in the ganglion cell, and nerve fibre layers in the parafovea and also that the border between them was unrecognisable (Figure 5). This hyperreflective complex shadowing effect relatively masked the photoreceptor hyperreflectivity except at the foveal region, due to the absence of the hyperreflective complex in the fovea.

Figure 1.

Fundus photograph showing a cherry red spot in the macula of both eyes

Figure 2.

Infrared autofluorescence fundus imaging demonstrating hypoautofluorescence in the parafovea of both eyes. This pattern is not visible in the fovea

Figure 3.

Blue autofluorescence study revealing the hyperreflective parafoveal area in both eyes with the fovea unaffected

Figure 4.

Fluorescein angiography showing parafoveal hypofluorescence in both eyes during the late phase

Figure 5.

Optical coherence tomography showing hyperreflectivity with a shadowing effect on the outer retinal layers in the parafovea. The foveal area is normal

Accumulation of metabolic products with lipofuscin-like autofluorescence characteristics in the inner retina explains all these findings. The sialyloligosaccharide accumulation causes hyperreflectance on BAF and OCT, and hyporeflectivity in IRAF and FA by creating a blocking effect.