Mild clinical presentation in KLHL40-related nemaline myopathy (NEM 8).

Nemaline myopathies are clinically and genetically heterogeneous muscle diseases characterized by the presence of nemaline bodies (rods) in muscle fibers. Mutations in the KLHL40 (kelch-like family member 40) gene (NEM 8) are common cause of severe/lethal nemaline myopathy. We report an 8-year-old girl born to consanguineous Moroccan parents, who presented with hypotonia and poor sucking at birth, delayed motor development, and further mild difficulties in walking and fatigability. A muscle biopsy revealed the presence of nemaline bodies. KLHL40 gene Sanger sequencing disclosed a never before reported pathogenic homozygous mutation which resulted in absent KLHL40 protein expression in the muscle. This further expands the phenotypical spectrum of KLHL40 related nemaline myopathy

Leveraging Natural History Data in One- and Two-Arm Hierarchical Bayesian Studies of Rare Disease Progression

peer reviewedThe small sample sizes inherent in rare and pediatric disease settings offer significant challenges for clinical trial design. In such settings, Bayesian adaptive trial methods can often pay dividends, allowing the sensible incorporation of auxiliary data and other relevant information to bolster that collected by the trial itself. Previous work has also included the use of one-arm trials augmented by the participants’ own natural history data, from which the future course of the disease in the absence of intervention can be predicted. Patient response can then be defined by the degree to which post-intervention observations are inconsistent with the predicted “natural” trajectory. While such trials offer obvious advantages in efficiency and ethical hazard (since they expose no new patients to a placebo, anathema to patients or their parents and caregivers), they can offer no protection against bias arising from the presence of any “placebo effect,” the tendency of patients to improve merely by being in the trial. In this paper, we investigate the impact of both static and transient placebo effects on one-arm responder studies of this type, as well as two-arm versions that incorporate a small concurrent placebo group but still borrow strength from the natural history data. We also propose more traditional Bayesian changepoint models that specify a parametric functional form for the patient’s post-intervention trajectory, which in turn allow quantification of the treatment benefit in terms of the model parameters, rather than semi-parametrically in terms of a response relative to some “null” model. We compare the operating characteristics of our designs in the context of an ongoing investigation of centronuclear myopathies (CNMs), a group of congenital neuromuscular diseases whose most common and severe form is X-linked, affecting approximately 1 in 50,000 newborn boys. Our results indicate our two-arm responder and changepoint methods can offer protection against placebo effects, improving power while protecting the trial’s Type I error rate. However, further research into innovative trial designs as well as ongoing dialog with regulatory authorities remain critically important in rare disease research

Les oligonucléotides anti-sens dans la SMA

Une révolution est actuellement en cours dans le domaine des maladies neuromusculaires avec l’arrivée de nouvelles thérapies. L’amyotrophie spinale (SMA ou spinal muscular atrophy) est parmi les maladies pionnières de ce bouleversement thérapeutique. Le premier traitement approuvé et mis sur le marché en Europe et aux États-Unis est un oligonucléotide antisens dénommé nusinersen et commercialisé par le laboratoire Biogen sous le nom de Spinraza®. Il a comme indication les SMA de types 1, 2 et 3. La première injection de Spinraza® dans le cadre d’une ATU/EAP (Autorisation Temporaire d’Utilisation/Expanded Access Program ou programmes d’accès étendu) a été réalisée en France par le centre d’essais l-Motion. Les résultats des essais cliniques et des données de la littérature sur l’utilisation du nusinersen dans la SMA infantile sont discutés dans cette revue. Ces études rapportent une amélioration de la fonction motrice chez les patients SMA tous types confondus y compris les patients de type 3 [

Caractérisation génotypique et phénotypique des patients Becker avec délétion des exons 45 à 55

The therapy development in DMD has been largely inspired by the clinical milder phenotype of Becker (BMD) patients. Phenotype variability within the same mutation has been a major concern in multi-exon skipping strategy development. In recent studies from our group BMDΔ45-55 patients were reported with various degree of severity. In order to study the genotype – phenotype correlation within this specific mutation cohort, we performed a retrospective analysis of French UMD-DMD data base and established the detailed phenotype characterization in 50 BMDΔ45-55 patients.Here we present the largest cohort of BMDΔ45-55 and propose a clinical severity scale (CSS) for the retrospective description of the natural history evolution of the skeletal muscle presentation in this specific deletion. With the aim of investigating the phenotype variability in BMD patients within the same genetic mutation, we performed whole genome sequencing in 19 BMDΔ45-55 in order to identify pathogenic variants in cardiac genes and in gene modifiers described in DMD.Le développement de la thérapie dans la DMD a été largement inspiré par le phénotype clinique plus modéré des patients Becker (BMD). La variabilité phénotypique au sein d'une même mutation a été une préoccupation majeure dans le développement de stratégies de sauts d'exons multiples. Dans des études récentes de notre groupe, des patients BMDΔ45-55 ont été identifiés avec divers degrés de gravité. Afin d'étudier la corrélation génotype – phénotype au sein de cette cohorte de mutations spécifiques, nous avons réalisé une analyse rétrospective des données françaises UMD-DMDbase et établi la caractérisation détaillée du phénotype chez 50 patients BMDΔ45-55.Nous présentons ici la plus grande cohorte de BMDΔ45-55 et proposons une échelle de gravité clinique (CSS) pour la description rétrospective de l'évolution de l'histoire naturelle de la présentation du muscle squelettique dans cette délétion spécifique. Dans le but d'étudier la variabilité phénotypique chez les patients DMB au sein d'une même mutation génétique, nous avons effectué un séquençage du génome entier dans 19 BMDΔ45-55 afin d'identifier des variants pathogènes dans les gènes cardiaques et dans les modificateurs de gènes décrits dans la DMD

DMD and West syndrome.

Duchenne Muscular Dystrophy (DMD) is the most frequent muscular dystrophy in childhood, with a worldwide incidence of one in 5000 live male births. It is due to mutations in the dystrophin gene leading to absence of full-length dystrophin protein. Central nervous system involvement is well-known in Duchenne Muscular Dystrophy. The multiple dystrophin isoforms expressed in brain have important roles in cerebral development and functioning. The association of Duchenne Muscular Dystrophy with seizures has been reported, and there is a higher prevalence of epilepsy in Duchenne Muscular Dystrophy patients (between 6.3% and 12.3%) than in the general pediatric population (0.5-1%). Duchenne Muscular Dystrophy patients may present with focal seizures, generalized tonic-clonic seizures or absences. We report on two boys in whom Duchenne Muscular Dystrophy is associated with epileptic spasms and hypsarrhythmia that fulfil the criteria for West syndrome, thus extending the spectrum of seizure types described in Duchenne Muscular Dystrophy patients

miR-708-5p and miR-34c-5p are involved in nNOS regulation in dystrophic context

International audienceBackground: Duchenne (DMD) and Becker (BMD) muscular dystrophies are caused by mutations in the DMD gene coding for dystrophin, a protein being part of a large sarcolemmal protein scaffold that includes the neuronal nitric oxide synthase (nNOS). The nNOS was shown to play critical roles in a variety of muscle functions and alterations of its expression and location in dystrophic muscle fiber leads to an increase of the muscle fatigability. We previously revealed a decrease of nNOS expression in BMD patients all presenting a deletion of exons 45 to 55 in the DMD gene (BMDd45-55), impacting the nNOS binding site of dystrophin. Since several studies showed deregulation of microRNAs (miRNAs) in dystrophinopathies, we focused on miRNAs that could target nNOS in dystrophic context.Methods: By a screening of 617 miRNAs in BMDd45-55 muscular biopsies using TLDA and an in silico study to determine which one could target nNOS, we selected four miRNAs. In order to select those that targeted a sequence of 3′UTR of NOS1, we performed luciferase gene reporter assay in HEK393T cells. Finally, expression of candidate miRNAs was modulated in control and DMD human myoblasts (DMDd45-52) to study their ability to target nNOS.Results: TLDA assay and the in silico study allowed us to select four miRNAs overexpressed in muscle biopsies of BMDd45-55 compared to controls. Among them, only the overexpression of miR-31, miR-708, and miR-34c led to a decrease of luciferase activity in an NOS1-3′UTR-luciferase assay, confirming their interaction with the NOS1-3′UTR. The effect of these three miRNAs was investigated on control and DMDd45-52 myoblasts. First, we showed a decrease of nNOS expression when miR-708 or miR-34c were overexpressed in control myoblasts. We then confirmed that DMDd45-52 cells displayed an endogenous increased of miR-31, miR-708, and miR-34c and a decreased of nNOS expression, the same characteristics observed in BMDd45-55 biopsies. In DMDd45-52 cells, we demonstrated that the inhibition of miR-708 and miR-34c increased nNOS expression, confirming that both miRNAs can modulate nNOS expression in human myoblasts.Conclusion: These results strongly suggest that miR-708 and miR-34c, overexpressed in dystrophic context, are new actors involved in the regulation of nNOS expression in dystrophic muscle

miR-708-5p and miR-34c-5p are involved in nNOS regulation in dystrophic context

Abstract Background Duchenne (DMD) and Becker (BMD) muscular dystrophies are caused by mutations in the DMD gene coding for dystrophin, a protein being part of a large sarcolemmal protein scaffold that includes the neuronal nitric oxide synthase (nNOS). The nNOS was shown to play critical roles in a variety of muscle functions and alterations of its expression and location in dystrophic muscle fiber leads to an increase of the muscle fatigability. We previously revealed a decrease of nNOS expression in BMD patients all presenting a deletion of exons 45 to 55 in the DMD gene (BMDd45-55), impacting the nNOS binding site of dystrophin. Since several studies showed deregulation of microRNAs (miRNAs) in dystrophinopathies, we focused on miRNAs that could target nNOS in dystrophic context. Methods By a screening of 617 miRNAs in BMDd45-55 muscular biopsies using TLDA and an in silico study to determine which one could target nNOS, we selected four miRNAs. In order to select those that targeted a sequence of 3′UTR of NOS1, we performed luciferase gene reporter assay in HEK393T cells. Finally, expression of candidate miRNAs was modulated in control and DMD human myoblasts (DMDd45-52) to study their ability to target nNOS. Results TLDA assay and the in silico study allowed us to select four miRNAs overexpressed in muscle biopsies of BMDd45-55 compared to controls. Among them, only the overexpression of miR-31, miR-708, and miR-34c led to a decrease of luciferase activity in an NOS1-3′UTR-luciferase assay, confirming their interaction with the NOS1-3′UTR. The effect of these three miRNAs was investigated on control and DMDd45-52 myoblasts. First, we showed a decrease of nNOS expression when miR-708 or miR-34c were overexpressed in control myoblasts. We then confirmed that DMDd45-52 cells displayed an endogenous increased of miR-31, miR-708, and miR-34c and a decreased of nNOS expression, the same characteristics observed in BMDd45-55 biopsies. In DMDd45-52 cells, we demonstrated that the inhibition of miR-708 and miR-34c increased nNOS expression, confirming that both miRNAs can modulate nNOS expression in human myoblasts. Conclusion These results strongly suggest that miR-708 and miR-34c, overexpressed in dystrophic context, are new actors involved in the regulation of nNOS expression in dystrophic muscle

EGR2 mutation enhances phenotype spectrum of Dejerine-Sottas syndrome

International audienc

Nusinersen in patients older than 7 months with spinal muscular atrophy type 1: A cohort study.

OBJECTIVE: To evaluate the safety and clinical efficacy of nusinersen in patients older than 7 months with spinal muscular atrophy type 1 (SMA1). METHODS: Patients with SMA1 were treated with nusinersen by intrathecal injections as a part of the Expanded Access Program (EAP; NCT02865109). We evaluated patients before treatment initiation (M0) and at 2 months (M2) and 6 months (M6) after treatment initiation. Survival, respiratory, and nutritional data were collected. Motor function was assessed with the modified Hammersmith Infant Neurologic Examination Part 2 (HINE-2) and physiotherapist scales adjusted to patient age (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders and the Motor Function Measure 20 or 32). RESULTS: We treated 33 children ranging in age from 8.3 to 113.1 months between December 2016 and May 2017. All patients were alive and were continuing treatment at M6. Median progress on the modified HINE-2 score was 1.5 points after 6 months of treatment (p < 0.001). The need for respiratory support significantly increased over time. There were no statistically significant differences between patients presenting with 2 and those presenting with 3 copies of the survival motor neuron 2 (SMN2) gene. CONCLUSIONS: Our results are in line with the phase 3 study for nusinersen in patients with SMA1 treated before 7 months of age and indicate that patients benefit from nusinersen even at a later stage of the disease. CLINICALTRIALSGOV IDENTIFIER: NCT02865109. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with SMA1 who are older than 7 months, nusinersen is beneficial

Additional file 3: of miR-708-5p and miR-34c-5p are involved in nNOS regulation in dystrophic context

Table S1. Predictive candidate miRNA binding sites on the human NOS1 3’UTR (DOCX 12 kb