A new score combining compound muscle action potential (CMAP) amplitudes and motor score is predictive of motor outcome after AVXS-101 (Onasemnogene Abeparvovec) SMA therapy.

Spinal muscular atrophy 1 (SMA1) is a severe early genetic disease with degeneration of motor neurons. Motor development is still suboptimal after gene replacement therapy in symptomatic patients. In this study, compound muscle action potential (CMAP) amplitudes were explored as predictors of motor recovery after gene therapy. Thirteen symptomatic SMA1 patients were prospectively included at the Necker Enfants Malades Hospital, Paris, France (Cohort 1) and 12 at the other pediatric neuromuscular reference centers of the French Filnemus network (Cohort 2). In Cohort 1, median CMAP amplitudes showed the best improvement between baseline and the 12 months visit compared to the other tested nerves (ulnar, fibular and tibial). High median CMAP amplitudes at baseline was associated with unaided sitting achievement at M6 (AUC 90%). None of the patients with CHOPINTEND at M0 < 30/64 and median CMAP < 0.5 mV achieved unaided sitting at M6 and this result was confirmed on Cohort 2 used as an independent validation data. Thus, median CMAP amplitude is a valid biomarker for routine practice to predict sitting at M6. A median CMAP amplitude over 0.5 mV at baseline may predict better motor recovery.

[Prognostic factors of neurofibromatosis type 1-associated optic pathway gliomas in children]. / Facteurs pronostiques des gliomes des voies optiques associés à la neurofibromatose de type 1 chez les enfants.

INTRODUCTION: Optic pathway glioma (OPG) is a classic complication of neurofibromatosis type 1 (NF1) and can impair visual function in children with this condition. The objective of this study is to describe clinical, paraclinical and prognostic characteristics of OPG associated with NF1. MATERIALS AND METHODS: In this retrospective observational study of children followed for OPG associated with NF1 in a University Hospital, we analyzed the ophthalmological examination, brain and orbital imaging, management and the presence of associated endocrinopathy. RESULTS: We examined 114 children with NF1, of which 26 (22.81%) presented with OPG. Mean ages at diagnosis of NF1 and OPG were 3.83 years and 6.23 years, respectively. Mean visual acuity was 20/24.4 for the worse eye and 20/23.1 for the better eye. The RNFL (retinal nerve fiber layer) was thinner in subjects than in age-matched controls (p <0.0001). Retrochiasmal location of the OPG (DodgeC) was associated with lower binocular visual acuity than other locations and <20/32 (p=0.028); 28.03% of OPG (5 girls and 1 boy) were treated with chemotherapy, and the others were monitored; 19.23% had an associated endocrinopathy. CONCLUSIONS: OPG complicates 22.81% of NF1 cases in our series. Our study shows that retrochiasmal location of the glioma and female sex are poor prognostic factors. It also highlights the important role of OCT, since a decrease in RNFL is statistically associated with the presence of an OPG.

Use of a book to disclose a diagnosis of Duchenne muscular dystrophy to a young child: A pilot study.

Disclosing the diagnosis of Duchenne muscular dystrophy, a progressive genetic disease, to children requires taking the time to talk with them and to identify the emotions that they experience on a daily basis. At the Reference Center for Neuromuscular Diseases of Children in Marseille, to accompany the disclosure of the diagnosis to the child, we have created a book to facilitate communication and dialog in the parent-child relationship. A single-center and prospective study was conducted of nine children and nine families to evaluate the usefulness of this tool. The results show that the book was appreciated by families and mainly recommended by children and their parents. Children's understanding of the disease improved, especially for the 6-8-year-old age group. The children's mental state was better at school after using the tool. The book offered them support to express their mood. As an accompaniment, this mediator tool helps parents and children alike. Caregivers use it as a support for the children to have a place to share their thoughts and emotions, from the very beginning of the follow-up. It helps build the child-parent-caregiver triad.

Spinal muscular atrophy (SMA) type I (Werdnig-Hoffmann disease).

Spinal muscular atrophy type I, also called Werdnig-Hoffmann disease, is the most serious form. The disease appears before the age of 6 months and is characterized by major global hypotonia and abolition of tendon reflexes, with children never being able to sit unaided. Cognitive development is normal and the expressive gaze of these children contrasts with the paralytic attitude. Respiratory involvement predominates in the intercostal muscles, and sometimes brainstem involvement are all serious aspects of the disease. Type I spinal muscular atrophy has been subdivided into 3 groups: - type IA, the clinical signs of which set in between birth and 15 days of life with sudden severe motor impairment, sucking-swallowing disorders attesting to bulbar involvement, respiratory distress. - type IB with onset of symptoms before the age of 3 months, which implies no head control - type IC starting between 3 and 6 months with the possibility of checking head control, often referred to as "I bis" by French practitioners. The development and use of innovative therapies in recent years does actually change the natural course of this disease. But we do not know for sure what the long-term evolution of infants who received these new therapies will be. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Identification of novel pathogenic copy number variations in Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth disease (CMT) is a hereditary sensory-motor neuropathy characterized by a strong clinical and genetic heterogeneity. Over the past few years, with the occurrence of whole-exome sequencing (WES) or whole-genome sequencing (WGS), the molecular diagnosis rate has been improved by allowing the screening of more than 80 genes at one time. In CMT, except the recurrent PMP22 duplication accounting for about 60% of pathogenic variations, pathogenic copy number variations (CNVs) are rarely reported and only a few studies screening specifically CNVs have been performed. The aim of the present study was to screen for CNVs in the most prevalent genes associated with CMT in a cohort of 200 patients negative for the PMP22 duplication. CNVs were screened using the Exome Depth software on next generation sequencing (NGS) data obtained by targeted capture and sequencing of a panel of 81 CMT associated genes. Deleterious CNVs were identified in four patients (2%), in four genes: GDAP1, LRSAM1, GAN, and FGD4. All CNVs were confirmed by high-resolution oligonucleotide array Comparative Genomic Hybridization (aCGH) and/or quantitative PCR. By identifying four new CNVs in four different genes, we demonstrate that, although they are rare mutational events in CMT, CNVs might contribute significantly to mutational spectrum of Charcot-Marie-Tooth disease and should be searched in routine NGS diagnosis. This strategy increases the molecular diagnosis rate of patients with neuropathy.

Retrospective study of 75 children with peripheral inherited neuropathy: Genotype-phenotype correlations.

INTRODUCTION: Charcot-Marie-Tooth disease (CMT) is an inherited peripheral neuropathy with an impact on patients' quality of life and wide genetic heterogeneity. Next-generation sequencing (NGS) has extended the molecular diagnosis. This study aims to describe a cohort of patients with CMT onset in childhood to explore genotype-phenotype correlations. MATERIAL AND METHODS: This is a retrospective and single-center study. Between 1992 and 2016, patients with CMT diagnosed in childhood and a molecular diagnosis were included. The follow-up was done at the Marseille Timone Teaching hospital and symptoms were retrieved over time in the patients' files, as well as from molecular data and an electrodiagnostic exam. We distinguished three groups: PMP22 compared CMT (CMT1A), MFN2 compared CMT (CMT2A2) and "all genes except PMP22". RESULTS: Seventy-five patients were included with 11 different genes involved, PMP22 being the most frequent (61.3%), then MFN2 (14.7%) and other sporadic mutations in various genes. Limitations in walking tended to occur earlier and more often, and distal strength impairment tended to progress further in CMT2A2 and "others genes than PMP22". The mean age at diagnosis was 8.4 years with a mean age when parents first expressed concern of 4.1 years. Only three patients lost their ability to walk. We describe two cases of digenism and one case of GAN mutation with a CMT-like presentation. An electromyogram was not systemically performed. CONCLUSION: There is a wide genetic and clinical heterogeneity in CMT. We tend to describe more severe patterns in CMT2A2 and less progressive presentations in CMT1A considering distal strength impairment and limitations walking. Prospective studies with more objective principal judgement criteria would be necessary to confirm these observations.