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Previous imaging studies assessing the relationship between white matter (WM) damage and matter (GM) atrophy have raised the concern that Multiple Sclerosis (MS) WM lesions may affect measures of GM volume by inducing voxel misclassification during intensity-based tissue segmentation. Here, we quantified this misclassification error in simulated and real MS brains using a lesion-filling method. Using this method, we also corrected GM measures in patients before comparing them with controls in order to assess the impact of this lesion-induced misclassification error in clinical studies. We found that higher WM lesion volumes artificially reduced total GM volumes. In patients, this effect was about 72% of that predicted by simulation. Misclassified voxels were located at the GM/WM border and could be distant from lesions. Volume of individual deep gray matter (DGM) structures generally decreased with higher lesion volumes, consistent with results from total GM. While preserving differences in GM volumes between patients and controls, lesion-filling correction revealed more lateralised DGM shape changes in patients, which were not evident with the original images. Our results confirm that WM lesions can influence MRI measures of GM volume and shape in MS patients through their effect on intensity-based GM segmentation. The greater effect of lesions at increasing levels of damage supports the use of lesion-filling to correct for this problem and improve the interpretability of the results. Volumetric or morphometric imaging studies, where lesion amount and characteristics may vary between groups of patients or change over time, may especially benefit from this correction.

Neurodegeneration is the main cause for permanent disability in multiple sclerosis. The effect of current immunomodulatory treatments on neurodegeneration is insufficient. Therefore, direct neuroprotection and myeloprotection remain an important therapeutic goal. Targeting acid-sensing ion channel 1 (encoded by the ASIC1 gene), which contributes to the excessive intracellular accumulation of injurious Na(+) and Ca(2+) and is over-expressed in acute multiple sclerosis lesions, appears to be a viable strategy to limit cellular injury that is the substrate of neurodegeneration. While blockade of ASIC1 through amiloride, a potassium sparing diuretic that is currently licensed for hypertension and congestive cardiac failure, showed neuroprotective and myeloprotective effects in experimental models of multiple sclerosis, this strategy remains untested in patients with multiple sclerosis. In this translational study, we tested the neuroprotective effects of amiloride in patients with primary progressive multiple sclerosis. First, we assessed ASIC1 expression in chronic brain lesions from post-mortem of patients with progressive multiple sclerosis to identify the target process for neuroprotection. Second, we tested the neuroprotective effect of amiloride in a cohort of 14 patients with primary progressive multiple sclerosis using magnetic resonance imaging markers of neurodegeneration as outcome measures of neuroprotection. Patients with primary progressive multiple sclerosis underwent serial magnetic resonance imaging scans before (pretreatment phase) and during (treatment phase) amiloride treatment for a period of 3 years. Whole-brain volume and tissue integrity were measured with high-resolution T(1)-weighted and diffusion tensor imaging. In chronic brain lesions of patients with progressive multiple sclerosis, we demonstrate an increased expression of ASIC1 in axons and an association with injury markers within chronic inactive lesions. In patients with primary progressive multiple sclerosis, we observed a significant reduction in normalized annual rate of whole-brain volume during the treatment phase, compared with the pretreatment phase (P = 0.018, corrected). Consistent with this reduction, we showed that changes in diffusion indices of tissue damage within major clinically relevant white matter (corpus callosum and corticospinal tract) and deep grey matter (thalamus) structures were significantly reduced during the treatment phase (P = 0.02, corrected). Our results extend evidence of the contribution of ASIC1 to neurodegeneration in multiple sclerosis and suggest that amiloride may exert neuroprotective effects in patients with progressive multiple sclerosis. This pilot study is the first translational study on neuroprotection targeting ASIC1 and supports future randomized controlled trials measuring neuroprotection with amiloride in patients with multiple sclerosis.

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Whole exome sequencing continues to end the diagnostic odyssey for a number of patients and expands our knowledge of phenotypes associated with gene mutations. We describe an 11-year-old female patient with a constellation of symptoms including congenital cataracts, gut dysmotility, sensory neuropathy, and bifrontal polymicrogyria. Whole exome sequencing was performed and identified a de novo heterozygous missense mutation in the ATPase motor domain of cytoplasmic dynein heavy chain 1 (DYNC1H1), which is known to be involved in neuronal migration and retrograde axonal transport. The mutation was found to be highly damaging by multiple prediction programs. The residue is highly conserved, and reported mutations in this gene result in a variety of phenotypes similar to that of our patient. We report only the second case of congenital cataracts and the first of gut dysmotility in a patient with DYNC1H1, thus expanding the spectrum of disease seen in DYNC1H1 dyneinopathies.

Cockayne syndrome (CS) is a rare progeroid disorder characterized by multisystem degeneration, including neurological dysfunction, for which deep brain stimulation (DBS) is a proposed treatment. This study represents only the third case of DBS for CS-associated movement disorder and the first in which both proposed targets had devices implanted, allowing for direct comparison. A case of DBS for CS-associated movement disorder is presented. Previous literature documents two cases with one targeting the ventral intermediate nucleus of the thalamus (VIM) and the other targeting the globus pallidus interna (GPi). Our patient underwent stimulation of GPi nuclei followed by repositioning to VIM nuclei with improved symptom control using VIM stimulation. In all cases, there was a significant clinical benefit without off-target effects. CS-associated movement disorder exhibits phenotypic variability for which DBS is a viable treatment. Target selection should be driven by clinical phenotype.

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