PMC6249318_01
(A) Midsagittal MRI at age 3 showing no cerebellar changes at that time. (B) Midsagittal MRI at age 11 showing evidence of asymmetric volume loss within the superior and middle components of the cerebellar vermis with preserved volume of the inferior component (red outline). (C) Axial plane MRI exhibiting faint linear/T2 signal hypointensities within the Pons (red arrow).
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F1
Previously performed neuropsychological testing showed a below average IQ and an MRI of the brain at age 3 was normal (Figure 1A). Brain MRI revealed asymmetric volume loss within the superior and middle aspects of the cerebellar vermis relative to the inferior aspect (Figure 1B) and faint linear T2 signal hypointensities within the pons (Figure 1C), findings that have been shown to be associated with ARSACS.
(A) Fundus photography of the right and left eyes demonstrating peripapillary retinal nerve fiber hypertrophy and white striations emanating adjacent to the optic nerve. (B) Posterior pole Optical Coherence Tomography demonstrating hypertrophy of the retinal nerve fiber layer and other inner retinal layers. (C) Selected cross sections of the right and left eye demonstrating hypertrophy of the retinal nerve fiber layer and other inner retinal layers. Colors correspond to the retinal layers depicted above.
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F2
On examination, he had gaze-evoked nystagmus and saccadic dysmetria with undershoot saccades in all directions, prominent white striations emanating adjacent to the optic nerve withdistinct optic disc margins on fundoscopy (Figure 2A), and symmetric pupils with no afferent defect. Fundoscopic photography and Optical Coherence Tomography both demonstrated hypertrophy of the retinal nerve fiber layer and other retinal layers (Figures 2B,C), findings also observed in ARSACS.
Chromosomal microarray showing 1.422 megabase loss in the 13q12.12 region containing 14 different genes, including the SACS gene.
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F3
Initial chromosome microarray then showed a 1.422 megabase loss in the 13q12.12 region (Figure 3), of which there are 14 genes present.