Introduction: Myelin oligodendrocyte glycoprotein antibodies (MOG-abs) are associated with demyelinating diseases. Leptomeningeal enhancement occurs in 6% of adult MOG-abs patients but rates in pediatric MOG-abs patients are unknown. Methods: Retrospective review of pediatric MOG-abs patients was performed. Results: Twenty-one patients (7 boys, 14 girls) were included with an average age of 8.6 years (range 2-15 years). Seven of 21 (33%) pediatric MOG-abs patients had leptomeningeal enhancement. Two patients’ relapses were manifested by leptomeningeal enhancement alone and another patient presented with seizures, encephalopathy, and aseptic meningitis without demyelinating lesions. Cerebrospinal fluid pleocytosis was seen in both leptomeningeal (4/7 patients) and nonleptomeningeal enhancement (10/14 patients). Interestingly, 3 patients with leptomeningeal enhancement had normal cerebrospinal fluid white blood cell count. Cortical edema was more likely in patients with leptomeningeal enhancement (P =.0263). Conclusion: We expand the clinical spectrum of anti-MOG antibody–associated disorder. Patients with recurrent leptomeningeal enhancement without demyelinating lesions should be tested for MOG antibodies.

Alexander disease is a rare, progressive, and generally fatal neurological disorder that results from dominant mutations affecting the coding region of GFAP, the gene encoding glial fibrillary acidic protein, the major intermediate filament protein of astrocytes in the CNS. A key step in pathogenesis appears to be the accumulation of GFAP within astrocytes to excessive levels. Studies using mouse models indicate that the severity of the phenotype correlates with the level of expression, and suppression of GFAP expression and/or accumulation is one strategy that is being pursued as a potential treatment. With the goal of identifying biomarkers that indirectly reflect the levels of GFAP in brain parenchyma, we have assayed GFAP levels in two body fluids in humans that are readily accessible as biopsy sites: CSF and blood. We find that GFAP levels are consistently elevated in the CSF of patients with Alexander disease, but only occasionally and modestly elevated in blood. These results provide the foundation for future studies that will explore whether GFAP levels can serve as a convenient means to monitor the progression of disease and the response to treatment.

Objective: Genome sequencing (GS) is promising for unsolved leukodystrophies, but its efficacy has not been prospectively studied. Methods: A prospective time-delayed crossover design trial of GS to assess the efficacy of GS as a first-line diagnostic tool for genetic white matter disorders took place between December 1, 2015 and September 27, 2017. Patients were randomized to receive GS immediately with concurrent standard of care (SoC) testing, or to receive SoC testing for 4 months followed by GS. Results: Thirty-four individuals were assessed at interim review. The genetic origin of 2 patient's leukoencephalopathy was resolved before randomization. Nine patients were stratified to the immediate intervention group and 23 patients to the delayed-GS arm. The efficacy of GS was significant relative to SoC in the immediate (5/9 [56%] vs 0/9 [0%]; Wild–Seber, p < 0.005) and delayed (control) arms (14/23 [61%] vs 5/23 [22%]; Wild–Seber, p < 0.005). The time to diagnosis was significantly shorter in the immediate-GS group (log-rank test, p = 0.04). The overall diagnostic efficacy of combined GS and SoC approaches was 26 of 34 (76.5%, 95% confidence interval = 58.8–89.3%) in <4 months, greater than historical norms of <50% over 5 years. Owing to loss of clinical equipoise, the trial design was altered to a single-arm observational study. Interpretation: In this study, first-line GS provided earlier and greater diagnostic efficacy in white matter disorders. We provide an evidence-based diagnostic testing algorithm to enable appropriate clinical GS utilization in this population. ANN NEUROL 2020;88:264–273.

Leukodystrophies are a broad class of genetic disorders that result in disruption or destruction of central myelination. Although the mechanisms underlying these disorders are heterogeneous, there are many common symptoms that affect patients irrespective of the genetic diagnosis. The comfort and quality of life of these children is a primary goal that can complement efforts directed at curative therapies. Contained within this report is a systems-based approach to management of complications that result from leukodystrophies. We discuss the initial evaluation, identification of common medical issues, and management options to establish a comprehensive, standardized care approach. We will also address clinical topics relevant to select leukodystrophies, such as gallbladder pathology and adrenal insufficiency. The recommendations within this review rely on existing studies and consensus opinions and underscore the need for future research on evidence-based outcomes to better treat the manifestations of this unique set of genetic disorders.

N-methyl-D-aspartate receptors (NMDARs) mediate slow excitatory postsynaptic transmission in the central nervous system, thereby exerting a critical role in neuronal development and brain function. Rare genetic variants in the GRIN genes encoding NMDAR subunits segregated with neurological disorders. Here, we summarize the clinical presentations for 18 patients harboring 12 de novo missense variants in GRIN1, GRIN2A, and GRIN2B that alter residues in the M2 re-entrant loop, a region that lines the pore and is intolerant to missense variation. These de novo variants were identified in children with a set of neurological and neuropsychiatric conditions. Evaluation of the receptor cell surface expression, pharmacological properties, and biophysical characteristics show that these variants can have modest changes in agonist potency, proton inhibition, and surface expression. However, voltage-dependent magnesium inhibition is significantly reduced in all variants. The NMDARs hosting a single copy of a mutant subunit showed a dominant reduction in magnesium inhibition for some variants. These variant NMDARs also show reduced calcium permeability and single-channel conductance, as well as altered open probability. The data suggest that M2 missense variants increase NMDAR charge transfer in addition to varied and complex influences on NMDAR functional properties, which may underlie the patients’ phenotypes.

Background: Optic atrophy may be the sequela of optic nerve injury due to any insult, including isolated and syndromic genetic diseases. Alanyl-tRNA synthetase 2 (AARS2) pathogenic variants have been reported to cause leukodystrophy with ovarian failure, and cardiomyopathy (#615889) as well as combined oxidative phosphorylation deficiency-8 (#614096). We report a young child who presented with decreased vision due to optic atrophy and was found to harbor missense variants in the AARS2 gene expanding the phenotypic expression of the AARS2 gene.Materials and Methods: Single observational case report with genetic testing, laboratory testing, neurologic and ophthalmic clinical examinations, and neuroimaging performed at a tertiary academic medical center.Results: An 18-month old Korean boy was noted to have a progressive decline in visual function. The physical exam revealed bilateral optic atrophy, peripheral retinal bone spicule pigmentation, and absent patellar reflexes. Electromyography was consistent with demyelinating polyneuropathy. Magnetic resonance imaging (MRI) of the brain and spine showed cerebellar and supratentorial white matter multifocal changes with areas of restricted diffusion, and dorsal column signal abnormalities. Whole exome sequencing revealed two missense variants in the AARS2 gene [c.1519G>C (p.V507L) and c.2165G>A (p.R722Q)], found to be in trans on parental testing.Conclusions: Missense variants in the AARS2 gene are the likely cause of the retinopathy and optic atrophy in this patient. This finding expands the phenotypic spectrum of the AARS2 gene.