Fig. 3.

Neuropathological features of Patient 1.2 and 8. Patient 1.2: The posterior cerebellar cortex is affected by multiple necrotic lesions (demarcated by *) demonstrating atrophy of the molecular layer, Purkinje cell dropout and granule cell loss (A; LFB H&E) and total necrosis of the cortex and underlying white matter (B; LFB H&E). The basis pontis demonstrates a devastating lesion with total neuronal cell loss (C; red dashed line; LFB H&E). Scale bar = 100 μm.

Patient 8: The lower midbrain shows devastated inferior colliculus with prominent capillary proliferation (arrows), microvacuolation and severe neuronal cell loss (D; H&E). The thalamus (E; LFB H&E) and subthalamic nucleus (F; H&E) are devastated featuring prominent capillary proliferation (arrows), microvacuolation, severe neuronal cell loss and morphologically normal neurons scattered throughout (arrowhead). The occipital lobes reveal microvacuolation and laminar necrosis of the cortical layers within Broadmann area 17 (G; LFB H&E) with the underlying white matter demonstrating myelin pallor relative to otherwise preserved myelin. The cortex features microvacuolation, severe neuronal cell loss and capillary proliferation. Surviving neurons within the inferior colliculus lack complex I subunit expression (H; NDUFB8 IHC, arrows) while mitochondrial mass is high (I; SDHA IHC, arrows).