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PMC5946598_02
Electron microscopy of sural nerve biopsy at 6 months of age showing (A) an axon with early degeneration, featuring flocculent quality of the axoplasm (TEM, x23 000); (B) atrophic axon with thin myelin and associated debris underneath the myelin (left), adjacent to a relatively preserved axon with normal looking Schwann cell nucleus and myelin (right; TEM, x11 000); (C) Low power magnification on electron microscopy shows isolated axonal degeneration and thin myelin that could be physiological at that time in life, and many unmyelinating fibers. The presence of collagen pockets could indicate loss of unmyelinated fibers.
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The sural nerve biopsy showed axonal degeneration and secondary alteration of myelin (see Figure 1).
H&E staining of quadriceps muscle biopsy at 6 months of age showing a tiny group of small angulated atrophic fibers (enriched by arrows), which could suggest neuropathy (H&E, paraffin section, x400).
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Muscle biopsy from quadriceps showed nonspecific findings with a tiny focal group of small angulated atrophic fibers (see Figure 2).
T2-weighted magnetic resonance imaging (MRI) of the brain at 8 months of age showing thin corpus callosum and cerebral atrophy.
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Brain magnetic resonance imaging performed at 8 months old showed cerebral atrophy with delayed myelination pattern and diffusely thinned corpus callosum (see Figure 3).
PMC5946598_03
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PMC5946598_05
Electromyography (EMG) at right deltoid at 22 months: Upon activation, motor unit potentials has prolonged duration (10 milliseconds) and polyphasic morphology with amplitude up to 800 muV. Interference pattern was incomplete.
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Follow-up study at 22 months old at the right deltoid and right quadriceps muscles showed infrequent fibrillation at rest, but an increase in MUAP duration (9-10 milliseconds) with polyphasia on activation with decrease recruitment and incomplete interference pattern compatible to chronic denervation (see Figure 4).