Epileptic Spasms in Congenital Disorders of Glycosylation

Congenital disorders of glycosylation (CDG) are a group of rare metabolic diseases, characterized by impaired glycosylation. Multisystemic involvement is common and neurological impairment is notably severe and disabling, concerning the central and peripheral nervous system. Epilepsy is frequent, but detailed electroclinical description is rare. We describe, retrospectively, the electroclinical features in five children with CDG and epileptic spasms. Epileptic spasms were observed in patients with ALG1-, ALG6, ALG11-CDG and CDG-Ix, and occurred at an early age, before 6 months in all cases, except one who had spasms that started at 18 months. In this patient, spasms had an unusual aspect; they did not occur in clusters and were immediately preceded by a myoclonus. All but one child also presented rare myoclonias. On EEG, background activity was poorly organized with abundant posterior spike and fast rhythm activity, but without hypsarrhythmia. At the last evaluation (age range: 6-12 years), two patients still presented epileptic spasms and subcortical myoclonias, one showed rare generalized tonic-clonic seizures, and two were seizure-free. CDG disorders can be associated with epileptic spasms showing particular features, such as absence of hypsarrhythmia, posterior EEG anomalies, and an unusual combination of epileptic spasms with myoclonus. These features, associated with pre-existing developmental delay and subcortical myoclonias, may shift toward CDG screening. [Published with video sequence and supplemental EEG plates on www.epilepticdisorders.com].info:eu-repo/semantics/publishedVersio

Unusual consequences of status epilepticus in Dravet syndrome

AbstractAlthough status epilepticus (SE) affects the course of Dravet syndrome (DS), it rarely alters dramatically psychomotor outcome. We report an unusual pattern in 3 patients who following refractory SE lasting respectively 2, 7 and 12h experienced persistent and severe cognitive and motor deterioration. We compared these patients to published data and to personal experience in Necker hospital, to find links between severe outcome and clinical features such as treatment or duration of refractory SE. The key point was that anoxoischemic-like lesions appeared on MRI although cardiovascular function had remained stable. Therefore, neither hemodynamic failure, nor abnormalities of cardiac rhythm could explain the lesions and neurological worsening. For theoretical reasons the responsibility of therapy common for the 3 patients, e.g., barbiturates was suspected

Spectrum of Neuroradiologic Findings Associated with Monogenic Interferonopathies

The genetic interferonopathies are a heterogeneous group of disorders thought to be caused by the dysregulated expression of interferons and are now commonly considered in the differential diagnosis of children presenting with recurrent or persistent inflammatory phenotypes. With emerging therapeutic options, recognition of these disorders is increasingly important, and neuroimaging plays a vital role. In this article, we discuss the wide spectrum of neuroradiologic features associated with monogenic interferonopathies by reviewing the literature and illustrate these with cases from our institutions. These cases include intracerebral calcifications, white matter T2 hyperintensities, deep WM cysts, cerebral atrophy, large cerebral artery disease, bilateral striatal necrosis, and masslike lesions. A better understanding of the breadth of the neuroimaging phenotypes in conjunction with clinical and laboratory findings will enable earlier diagnosis and direct therapeutic strategies

Une hypoplasie ponto-cérébelleuse causée par l’accumulation d’un inositol phosphate = A disruption of inositol phosphates metabolism causes pontocerebellar hypoplasia

Les hypoplasies ponto-cérébelleuses forment un groupe de maladies neurodégénératives périnatales très rares, caractérisées par une hypoplasie ou une atrophie précoce du cervelet et du tronc cérébral, une structure cérébrale impliquée dans des fonctions vitales, notamment la respiration. La dégénérescence débute au cours du développement cérébral, souvent avant la naissance. Elle est responsable d’une microcéphalie, parfois congénitale, mais plus souvent d’apparition progressive. Les développements moteur et cognitif sont altérés dès les premiers mois de vie, et la maladie est le plus souvent mortelle dans l’enfance. Ces maladies sont principalement génétiques et transmises selon un mode autosomique récessif. Près de 20 gènes responsables ont été identifiés à ce jour [1, 2]. La plupart sont impliqués dans l’épissage et la maturation d’ARN codants ou non codants, alors que les autres gènes jouent des rôles différents. Les mécanismes cellulaires et moléculaires responsables de la dégénérescence sont mal compris

Effective connectivity reveals strategy differences in an expert calculator

Mathematical reasoning is a core component of cognition and the study of experts defines the upper limits of human cognitive abilities, which is why we are fascinated by peak performers, such as chess masters and mental calculators. Here, we investigated the neural bases of calendrical skills, i.e. the ability to rapidly identify the weekday of a particular date, in a gifted mental calculator who does not fall in the autistic spectrum, using functional MRI. Graph-based mapping of effective connectivity, but not univariate analysis, revealed distinct anatomical location of “cortical hubs” supporting the processing of well-practiced close dates and less-practiced remote dates: the former engaged predominantly occipital and medial temporal areas, whereas the latter were associated mainly with prefrontal, orbitofrontal and anterior cingulate connectivity. These results point to the effect of extensive practice on the development of expertise and long term working memory, and demonstrate the role of frontal networks in supporting performance on less practiced calculations, which incur additional processing demands. Through the example of calendrical skills, our results demonstrate that the ability to perform complex calculations is initially supported by extensive attentional and strategic resources, which, as expertise develops, are gradually replaced by access to long term working memory for familiar material

The human OPA1delTTAG mutation induces premature age-related systemic neurodegeneration in mouse

Dominant optic atrophy is a rare inherited optic nerve degeneration caused by mutations in the mitochondrial fusion gene OPA1. Recently, the clinical spectrum of dominant optic atrophy has been extended to frequent syndromic forms, exhibiting various degrees of neurological and muscle impairments frequently found in mitochondrial diseases. Although characterized by a specific loss of retinal ganglion cells, the pathophysiology of dominant optic atrophy is still poorly understood. We generated an Opa1 mouse model carrying the recurrent Opa1(delTTAG) mutation, which is found in 30% of all patients with dominant optic atrophy. We show that this mouse displays a multi-systemic poly-degenerative phenotype, with a presentation associating signs of visual failure, deafness, encephalomyopathy, peripheral neuropathy, ataxia and cardiomyopathy. Moreover, we found premature age-related axonal and myelin degenerations, increased autophagy and mitophagy and mitochondrial supercomplex instability preceding degeneration and cell death. Thus, these results support the concept that Opa1 protects against neuronal degeneration and opens new perspectives for the exploration and the treatment of mitochondrial diseases

MINPP1 prevents intracellular accumulation of the chelator inositol hexakisphosphate and is mutated in Pontocerebellar Hypoplasia

Inositol polyphosphates are vital metabolic and secondary messengers, involved in diverse cellular functions. Therefore, tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, we describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the multiple inositol-polyphosphate phosphatase 1 gene (MINPP1). Patients are found to have a distinct type of Pontocerebellar Hypoplasia with typical basal ganglia involvement on neuroimaging. We find that patient-derived and genome edited MINPP1−/− induced stem cells exhibit an inefficient neuronal differentiation combined with an increased cell death. MINPP1 deficiency results in an intracellular imbalance of the inositol polyphosphate metabolism. This metabolic defect is characterized by an accumulation of highly phosphorylated inositols, mostly inositol hexakisphosphate (IP6), detected in HEK293 cells, fibroblasts, iPSCs and differentiating neurons lacking MINPP1. In mutant cells, higher IP6 level is expected to be associated with an increased chelation of intracellular cations, such as iron or calcium, resulting in decreased levels of available ions. These data suggest the involvement of IP6-mediated chelation on Pontocerebellar Hypoplasia disease pathology and thereby highlight the critical role of MINPP1 in the regulation of human brain development and homeostasis

Pharmacological screening using an FXN-EGFP cellular genomic reporter assay for the therapy of Friedreich ataxia

Copyright @ 2013 Li et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Friedreich ataxia (FRDA) is an autosomal recessive disorder characterized by neurodegeneration and cardiomyopathy. The presence of a GAA trinucleotide repeat expansion in the first intron of the FXN gene results in the inhibition of gene expression and an insufficiency of the mitochondrial protein frataxin. There is a correlation between expansion length, the amount of residual frataxin and the severity of disease. As the coding sequence is unaltered, pharmacological up-regulation of FXN expression may restore frataxin to therapeutic levels. To facilitate screening of compounds that modulate FXN expression in a physiologically relevant manner, we established a cellular genomic reporter assay consisting of a stable human cell line containing an FXN-EGFP fusion construct, in which the EGFP gene is fused in-frame with the entire normal human FXN gene present on a BAC clone. The cell line was used to establish a fluorometric cellular assay for use in high throughput screening (HTS) procedures. A small chemical library containing FDA-approved compounds and natural extracts was screened and analyzed. Compound hits identified by HTS were further evaluated by flow cytometry in the cellular genomic reporter assay. The effects on FXN mRNA and frataxin protein levels were measured in lymphoblast and fibroblast cell lines derived from individuals with FRDA and in a humanized GAA repeat expansion mouse model of FRDA. Compounds that were established to increase FXN gene expression and frataxin levels included several anti-cancer agents, the iron-chelator deferiprone and the phytoalexin resveratrol.Muscular Dystrophy Association (USA), the National Health and Medical Research Council (Australia), the Friedreich’s Ataxia Research Alliance (USA), the Brockhoff Foundation (Australia), the Friedreich Ataxia Research Association (Australasia), Seek A Miracle (USA) and the Victorian Government’s Operational Infrastructure Support Program