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Next generation sequencing (NGS) is strategically used for genetic diagnosis in patients with Charcot–Marie–Tooth disease (CMT) and related disorders called non-syndromic inherited peripheral neuropathies (NSIPN) in this paper. With over 100 different CMT-associated genes involved and ongoing discoveries, an important interlaboratory diversity of gene panels exists at national and international levels. Here, we present the work of the French National Network for Rare Neuromuscular Diseases (FILNEMUS) genetic diagnosis section which coordinates the seven French diagnosis laboratories using NGS for peripheral neuropathies. This work aimed to establish a unique, simple and accurate gene classification based on literature evidence. In NSIPN, three subgroups were usually distinguished: (1) HMSN, Hereditary Motor Sensory Neuropathy, (2) dHMN, distal Hereditary Motor Neuropathy, and (3) HSAN, Hereditary Sensory Autonomic Neuropathy. First, we reported ClinGen evaluation, and second, for the genes not evaluated yet by ClinGen, we classified them as “definitive” if reported in at least two clinical publications and associated with one report of functional evidence, or “limited” otherwise. In total, we report a unique consensus gene list for NSIPN including the three subgroups with 93 genes definitive and 34 limited, which is a good rate for our gene’s panel for molecular diagnostic use.

Background Due to their health condition, patients with neuromuscular diseases (NMD) are at greater risk of developing serious complications with COVID-19. The objective of this study was to analyze the prevalence of COVID-19 among NMD patients and the risk factors for its impact and severity during the first wave of the pandemic. Clinical data were collected from NMD-COVID-19 patients, between March 25, 2020 and May 11, 2020 in an anonymous survey carried out by expert physicians from the French Health Care Network Filnemus. Results Physicians reported 84 patients, including: 34 with myasthenia gravis, 27 with myopathy and 23 with neuropathy. COVID-19 had no effect on NMD for 48 (58%) patients and 48 (58%) patients developed low COVID-19 severity. COVID-19 caused the death of 9 (11%) NMD patients. Diabetic patients were at greater risk of dying. Patients with diabetes, hypertension or severe forms of NMD had a higher risk of developing a moderate or severe form of COVID-19. In our cohort, corticosteroids and other immunosuppressants were not significantly associated with higher COVID-19 severity for acquired NMD. Conclusion During this period, a small percentage of French NMD patients was affected by COVID-19 compared to the general French population and COVID-19 had a limited short-term effect on them. Diabetes, hypertension and a severe degree of NMD were identified as risk factors of unfavorable outcome following COVID-19. Conversely, in our cohort of patients with acquired NMD, corticosteroids or other immunosuppressants did not appear to be risk factors for more severe COVID-19.

International audience; Next-generation sequencing (NGS) gene-panel-based analyses constitute diagnosis strategies which are adapted to the genetic heterogeneity within the field of myopathies, including more than 200 implicated genes to date. Nonetheless, important inter-laboratory diversity of gene panels exists at national and international levels, complicating the exchange of data and the visibility of the diagnostic offers available for referring neurologists. To address this issue, we here describe the initiative of the genetic diagnosis section of the French National Network for Rare Neuromuscular Diseases (Filière Nationale des Maladies Rares Neuromusculaires, FILNEMUS), which led to set up a consensual nationwide diagnostic strategy among the nine French genetic diagnosis laboratories using NGS for myopathies. The strategy is based on the determination of 13 clinical and/or histological entry-diagnosis groups, and consists for each group either in a successive NGS analysis of a "core gene list" followed in case of a negative result by the analysis of an "exhaustive gene list", or in the NGS analysis of a "unique exhaustive gene list".

Resume Le lancement d’Horizon 2020, 8 e programme cadre de recherche et de developpement (PCRD) de l’Union Euro-peenne, dote de 79 milliards d’euros, est l’occasion de faire le bilan de la participation de la France aux precedents PCRD. Elle n’est a la hauteur ni de son poids scientifique, ni de son investissement financier. Alors que la France a contribue au budget recherche de l’Union Europeenne (7 e PCRD) a hauteur de 16,5 a 17 %, le retour monetaire assure par le financement de projets coordonnes auxquels ses equipes participent est de l’ordre de 12,5 a 13 %. C’est un manque a gagner de 600 millions d’euros. Meme si la situation doit etre nuancee par type d’activite, la France, en recherche clinique, apparait en retrait et moins engagee dans les appels a projets europeens par comparaison avec ses voisins. Si la France possede des atouts (financement assure de la recherche clinique, structuration de reseaux thematiques, lancement de grands plans nationaux), elle est penalisee par l’eparpillement des ressources au nom de la politique d’amenagement du territoire, le manque d’approche multidisciplinaire et la meconnaissance du fonctionnement de Horizon 2020 par la communaute medicale et scientifique et les institutions auxquelles elles appartiennent. Les solutions envisagees pour inciter au depot de projets coordonnes ou associant des equipes francaises en recherche clinique et aider a leur montage sont de trois ordres : • elargir la vision de nos enfants, etudiants et collaborateurs et les aider a s’adapter a la mondialisation des connaissances tout au long de leur cheminement educatif et professionnel ; • valoriser les actions europeennes pour agir sur le contexte europeen et faire evoluer les mentalites ; • aider et accompagner les porteurs de projets en mutualisant les competences autour d’un nombre limite de centres d’expertise d’aide au montage.

Purpose:When Coronary Computed Tomography (CCT) detects coronary obstruction, patients are regularly referred to invasive angiogram. With higher sensitivity than specificity, CCT might induce unnecessary angiograms (“false positive CCT”). We sought to determine the patients and CCT findings associated with false positive CCT. Methods: Patients were prospectively referred to CCT with a 64-slice CT scan for suspected CAD. Inclusion criteria were: 1) clinically suspected angina pectoris; or 2) suspected silent ischemia on resting EKG. Exclusion criteria were acute coronary syndrome and non sinus rhythm. Invasive coronary angiogram (ICA) was performed on the basis of CCT findings (stenosis >50%). Analysis was performed on a per patient basis. Results: Out of 702 patients, 228 had suspected significant stenosis by CCT and ICA was performed in 176 patients. Coronary stenosis >50% was not confirmed by ICA in 44 (25%). In multivariate analysis, we observed that atypical angina (OR 3.63,CI 1.43-9.66), silent ischemia (OR 5.11, CI 1.89-14.6) and number of suspected stenosed arteries by CCT (OR 1.81, CI 1.15-2.94) were independently predictive of false positive CCT (p < 0.05). Lesion location and coronary plaque characteristics did not impact on CCT accuracy. Conclusions:Performing CCT for atypical angina or silent ischemia is associated with higher rate of unnecessary invasive coronary angiograms. We failed to identify lesions characteristics prone to be “false positive” of CCT.

Etat des lieux. - Le coroscanner detecte les obstructions coronaires avec une grande sensibilite et pourrait etre utile au diagnostic le l'angor stable. Objectifs. - Dans cette etude pilote, nous avons prospectivement evalue la performance du coroscanner comme examen initial et determine la pertinence de cette strategie en fonction de la probabilite de la maladie coronaire. Methodes. - Cent quatre-vingt patients avec douleur thoracique suspecte d'angor ont ete evalues par coroscanner multicoupes. Une coronarographie n'etait indiquee que sur la base du coroscanner (stenose > 50%). Les patients ont ete classes en fonction de leur probabilite initiale de maladie coronaire en utilisant le score de Duke (faible, intermediaire, eleve). Un echec de la strategie etait defini comme realiser une coronarographie blanche (absence de stenose significative) ou la presence d'un evenement cardiaque a six mois chez les patients a coroscanner normal. Resultats. - La probabilite initiale de maladie coronaire etait de 53 ± 29%. Une stenose significative a ete detectee par scanner chez 51 patients et 47 (26%) ont ete coronarographies. Quinze patients (10%) ont eu une coronarographie blanche et un patient est decede alors qu'il n'avait pas de stenose au coroscanner. Les echecs de la strategie etaient de 8, 1,7 et 17% dans les groupes respectifs de probabilite de maladie coronaire faible, intermediaire et elevee (p = 0,015). Conclusions. - Le coroscanner comme etape initiale du diagnostic de l'angor stable est plus pertinent chez les patients a risque intermediaire de maladie coronaire. Chez les autres patients, une telle strategie est associee a un taux eleve de coronarographie blanche.

Objective: To investigate the molecular pathways disrupted by dominant spastin mutations in apparently unaffected skeletal muscle from patients with motor neuron disease (SPG4).Methods: The authors studied muscle of three individuals from two unrelated families affected by spastic paraplegia caused by spastin mutations. The authors compared RNA expression profiles to 7 normal and 13 pathologic muscle U95A profiles (Duchenne dystrophy, acute quadriplegic myopathy, and spinal muscular atrophy). Data were validated with U133A arrays with seven different control specimens. mRNA and protein confirmations were done for a subset of genes.Results: Both nonsense and missense mutations in the spastin gene disrupted microtubule pathways in nonpathologic tissue, including microtubule dynamics, stability, exocytosis, and endocytosis.Conclusions: Normal muscle can be used to uncover biochemical perturbation in motor neuron disease. Altered microtubule metabolism in SPG4-linked hereditary spastic paraplegia patients leads to pathology of the long descending tracks of motor neurons that likely have a stringent need for efficient microtubular transport. As many inherited neurologic conditions show a systemic biochemical defect with disease limited to neurons, our data have broader implications for biochemical pathway studies of many neurologic disorders.

Acute quadriplegic myopathy (AQM; also called "critical illness myopathy") shows acute muscle wasting and weakness and is experienced by some patients with severe systemic illness, often associated with administration of corticosteroids and/or neuroblocking agents. Key aspects of AQM include muscle atrophy and myofilament loss. Although these features are shared with neurogenic atrophy, myogenic atrophy in AQM appears mechanistically distinct from neurogenic atrophy. Using muscle biopsies from AQM, neurogenic atrophy, and normal controls, we show that both myogenic and neurogenic atrophy share induction of myofiber-specific ubiquitin/proteosome pathways (eg, atrogin-1). However, AQM patient muscle showed a specific strong induction of transforming growth factor (TGF)-beta/MAPK pathways. Atrophic AQM myofibers showed coexpression of TGF-beta receptors, p38 MAPK, c-jun, and c-myc, including phosphorylated active forms, and these same fibers showed apoptotic features. Our data suggest a model of AQM pathogenesis in which stress stimuli (sepsis, corticosteroids, pH imbalance, osmotic imbalance) converge on the TGF-beta pathway in myofibers. The acute stimulation of the TGF-beta/MAPK pathway, coupled with the inactivity-induced atrogin-1/proteosome pathway, leads to the acute muscle loss seen in AQM patients.

The more frequent manifestation of ophthalmological abnormalities in males, relative to females, is an unexplained feature of Leber's hereditary optic neuropathy (LHON) that suggests an X-linked modifying gene acting in concert with the pathogenic LHON mitochondrial DNA (mtDNA) mutation. In addition, segregation analysis of the optic neuropathy in LHON pedigrees was compatible with the presence of a recessive-modifying gene on chromosome X. According to this two-locus model, females would be affected only if homozygous or if they were susceptible to skewed X-inactivation. Attempts both to localize the putative LHON-modifying gene by linkage analysis and to find an excess of skewed X-inactivation in affected females were unsuccessful, although the inactivation pattern was only studied in DNA isolated from blood cells. We had the opportunity to analyze a wide range of tissues at autopsy, including the optic nerves and the retina, from two LHON female patients. We found no evidence of skewed X-inactivation in the affected tissues, thus weakening further the hypothesized involvement of a specific X chromosome locus in the pathophysiological expression of LHON. © 2003 Wiley-Liss, Inc.

The initiation of Horizon 2020--the European Union's 8th Framework Programme for Research and Innovation, allotted a budget of 79 billion euros--provides an opportunity to review France's participation in previous Framework Programmes. Indeed, French participation does not match either its scientific importance or its financial investment. While France contributed 16.5 to 17% of the EU's 7th Framework Programme research budget, its return through the funding of coordinated projects in which French teams are participating stands at around 12.5 to 13%, a shortfall of 600 million euros. Although the situation depends on the type of activity, French participation in clinical research appears to be smaller than that of its neighbours, with fewer responses to European calls for proposals. While France has many assets, which include the assured funding of clinical research, structured thematic networks and the initiation of major national programmes, it suffers from the dilution of resources due to France's regional development policy, the lack of multidisciplinarity and the ignorance of both the medical and scientific community and the institutions to which they belong as to how Horizon 2020 actually works. We propose three types of strategy to encourage proposals for coordinated clinical research projects or projects involving French teams, and to help in the drawing up of applications: Broaden the vision of our children, students and colleagues, helping them to adapt to the globalisation of knowledge throughout their educational and professional lives. Recognise the value of European actions to influence the European landscape and change mentalities. Help and support project initiators by pooling skills within a limited number of expert centres designed to assist them in their funding application. • Broaden the vision of our children, students and colleagues, helping them to adapt to the globalisation of knowledge throughout their educational and professional lives. • Recognise the value of European actions to influence the European landscape and change mentalities. • Help and support project initiators by pooling skills within a limited number of expert centres designed to assist them in their funding application.

Native Paralithodes camtschaticae hemocyanin is found as a mixture of dodecamers (24S; 80%) and hexamers (16S; 20%). Removal of Ca2+ ions by dialysis against EDTA-containing buffer solution at neutral pH induces complete dissociation of the 24S form into the 16S form. Under these conditions, a further increase in pH to 9.2 produces complete dissociation of the hexamers into monomers (5S). In both cases, the dissociation process is reversible. The dodecamer (24S) is composed of two different hexamers which can be discriminated only by ion-exchange chromatography in the presence of Ca2+ ions. At alkaline pH and in the presence of EDTA, two major monomeric fractions can be separated by ion-exchange chromatography: ParcI (60%) and ParcII (40%). The reassociation properties of the two fractions were studied separately to define their ability to form hexamers and dodecamers. The oxygen-binding properties of the different aggregation states were investigated. Native hemocyanin binds O2 co-operatively (nH = 3) and with low affinity (p50 ≈ 103 Torr). The two monomeric fractions, ParcI and ParcII, are not co-operative and the affinity is twice that of the native protein (p50 ≈ 65 and 52 Torr). Oxygen-binding measurements of native hemocyanin carried out at different pH values indicate a strong positive Bohr effect within the pH range 6.5–8.0 and an increase in oxygen affinity at pH below 6.5.

Changes in gene expression contribute to pathophysiological alterations following spinal cord injury (SCI). We examined gene expression over time (4 h, 24 h, 7 days) at the impact site, as well as rostral and caudal regions, following mild, moderate, or severe contusion SCI in rats. High-density oligonucleotide microarrays were used that included ∼27,000 genes/ESTs (Affymetrix RG-U34; A, B and C arrays), together with multiple analyses (MAS 5.0, dChip). Alterations after mild injury were relatively rapid (4 and 24 h), whereas they were delayed and prolonged after severe injury (24 h and 7 days). The number and magnitude of gene expression changes were greatest at the injury site after moderate injury and increased in rostral and caudal regions as a function of injury severity. Sham surgery resulted in expression changes that were similar to mild injury, suggesting the importance of using time-linked surgical controls as well as naive animals for these kinds of studies. Expression of many genes and ESTs was altered; these were classified functionally based on ontology. Overall representation of these functional classes varied with distance from the site of injury and injury severity, as did the individual genes that contributed to each functional class. Different clustering approaches were used to identify changes in neuronal-specific genes and several transcription factors that have not previously been associated with SCI. This study represents the most comprehensive evaluation of gene expression changes after SCI to date. The results underscore the power of microarray approaches to reveal global genomic responses as well as changes in particular gene clusters and/or families that may be important in the secondary injury cascade.

Variants of the copper-containing nitrite reductase (NiR) of Alcaligenes faecalis S6 were constructed by site-directed mutagenesis, by which the C-terminal histidine ligand (His145) of the Cu in the type-1 site was replaced by an alanine or a glycine. The type-1 sites in the NiR variants as isolated, are in the reduced form, but can be oxidized in the presence of external ligands, like (substituted) imidazoles and chloride. The reduction potential of the type-1 site of NiR-H145A reconstituted with imidazole amounts to 505 mV vs NHE (20 degrees C, pH 7, 10 mM imidazole), while for the native type-1 site it amounts to 260 mV. XRD data on crystals of the reduced and oxidized NiR-H145A variant show that in the reduced type-1 site the metal is 3-coordinated, but in the oxidized form takes up a ligand from the solution. With the fourth (exogenous) ligand in place the type-1 site is able to accept electrons at about the same rate as the wt NiR, but it is unable to pass the electron onto the type-2 site, leading to loss of enzymatic activity. It is argued that the uptake of an electron by the mutated type-1 site is accompanied by a loss of the exogenous ligand and a concomitant rise of the redox potential. This rise effectively traps the electron in the type-1 site.

Variants of the copper-containing nitrite reductase (NiR) of Alcaligenes faecalis S6 were constructed by site-directed mutagenesis, by which the C-terminal histidine ligand (His145) of the Cu in the type-1 site was replaced by an alanine or a glycine. The type-1 sites in the NiR variants as isolated, are in the reduced form, but can be oxidized in the presence of external ligands, like (substituted) imidazoles and chloride. The reduction potential of the type-1 site of NiR-H145A reconstituted with imidazole amounts to 505 mV vs NHE (20degreesC, pH 7, 10 mM imidazole), while for the native type-1 site it amounts to 260 mV. XRD data on crystals of the reduced and oxidized NiR-H145A variant show that in the reduced type-1 site the metal is 3-coordinated, but in the oxidized form takes up a ligand from the solution. With the fourth (exogenous) ligand in place the type-1 site is able to accept electrons at about the same rate as the wt NiR, but it is unable to pass the electron onto the type-2 site, leading to loss of enzymatic activity. It is argued that the uptake of an electron by the mutated type-1 site is accompanied by a loss of the exogenous ligand and a concomitant rise of the redox potential. This rise effectively traps the electron in the type-1 site.

Mutations in spastin cause the most common form of pure autosomal dominant hereditary spastic paraparesis (SPG4). Here, we report two Italian families affected with SPG4-linked HSP harboring two novel spastin mutations. SSCP/sequencing analysis of the spastin gene showed a single base pair deletion causing a frame-shift in one family (1442delT) and a missense mutation (1726T>C) resulting in a leucine to proline amino-acid change (L534P) in the other family. Total RNA from the mutant and the wild-type spastin allele in muscle biopsies from patients from the two affected families was quantitated. RNA expression was almost absent from the spastin allele harboring the single base pair deletion, while it was nearly normal for the spastin allele harboring the missense mutation. These data suggest that varying spastin RNA levels are found in out-of-frame and missense spastin mutations and imply different mechanisms involved in the molecular pathology of SPG4 linked HSP.