Autosomal recessive variants in TUBGCP2 alter the γ-tubulin ring complex leading to neurodevelopmental disease.

Microtubules help building the cytoskeleton of neurons and other cells. Several components of the gamma-tubulin (γ-tubulin) complex have been previously reported in human neurodevelopmental diseases. We describe two siblings from a consanguineous Turkish family with dysmorphic features, developmental delay, brain malformation, and epilepsy carrying a homozygous mutation (p.Glu311Lys) in TUBGCP2 encoding the γ-tubulin complex 2 (GCP2) protein. This variant is predicted to disrupt the electrostatic interaction of GCP2 with GCP3. In primary fibroblasts carrying the variant, we observed a faint delocalization of γ-tubulin during the cell cycle but normal GCP2 protein levels. Through mass spectrometry, we observed dysregulation of multiple proteins involved in the assembly and organization of the cytoskeleton and the extracellular matrix, controlling cellular adhesion and of proteins crucial for neuronal homeostasis including axon guidance. In summary, our functional and proteomic studies link TUBGCP2 and the γ-tubulin complex to the development of the central nervous system in humans

A guide to writing systematic reviews of rare disease treatments to generate FAIR-compliant datasets: building a Treatabolome

Abstract: Background: Rare diseases are individually rare but globally affect around 6% of the population, and in over 70% of cases are genetically determined. Their rarity translates into a delayed diagnosis, with 25% of patients waiting 5 to 30 years for one. It is essential to raise awareness of patients and clinicians of existing gene and variant-specific therapeutics at the time of diagnosis to avoid that treatment delays add up to the diagnostic odyssey of rare diseases’ patients and their families. Aims: This paper aims to provide guidance and give detailed instructions on how to write homogeneous systematic reviews of rare diseases’ treatments in a manner that allows the capture of the results in a computer-accessible form. The published results need to comply with the FAIR guiding principles for scientific data management and stewardship to facilitate the extraction of datasets that are easily transposable into machine-actionable information. The ultimate purpose is the creation of a database of rare disease treatments (“Treatabolome”) at gene and variant levels as part of the H2020 research project Solve-RD. Results: Each systematic review follows a written protocol to address one or more rare diseases in which the authors are experts. The bibliographic search strategy requires detailed documentation to allow its replication. Data capture forms should be built to facilitate the filling of a data capture spreadsheet and to record the application of the inclusion and exclusion criteria to each search result. A PRISMA flowchart is required to provide an overview of the processes of search and selection of papers. A separate table condenses the data collected during the Systematic Review, appraised according to their level of evidence. Conclusions: This paper provides a template that includes the instructions for writing FAIR-compliant systematic reviews of rare diseases’ treatments that enables the assembly of a Treatabolome database that complement existing diagnostic and management support tools with treatment awareness data

The TREAT-NMD DMD Global Database: analysis of more than 7,000 Duchenne muscular dystrophy mutations.

Analyzing the type and frequency of patient-specific mutations that give rise to Duchenne muscular dystrophy (DMD) is an invaluable tool for diagnostics, basic scientific research, trial planning, and improved clinical care. Locus-specific databases allow for the collection, organization, storage, and analysis of genetic variants of disease. Here, we describe the development and analysis of the TREAT-NMD DMD Global database (http://umd.be/TREAT_DMD/). We analyzed genetic data for 7,149 DMD mutations held within the database. A total of 5,682 large mutations were observed (80% of total mutations), of which 4,894 (86%) were deletions (1 exon or larger) and 784 (14%) were duplications (1 exon or larger). There were 1,445 small mutations (smaller than 1 exon, 20% of all mutations), of which 358 (25%) were small deletions and 132 (9%) small insertions and 199 (14%) affected the splice sites. Point mutations totalled 756 (52% of small mutations) with 726 (50%) nonsense mutations and 30 (2%) missense mutations. Finally, 22 (0.3%) mid-intronic mutations were observed. In addition, mutations were identified within the database that would potentially benefit from novel genetic therapies for DMD including stop codon read-through therapies (10% of total mutations) and exon skipping therapy (80% of deletions and 55% of total mutations)

RD-Connect, NeurOmics and EURenOmics: collaborative European initiative for rare diseases

Functional Genomics of Muscle, Nerve and Brain Disorder

Myologie et minorités ethniques

Une fois n’est pas coutume, la rubrique « Myologie dans le Monde » s’intéresse, non pas à un pays ou à une zone géographique donnée, mais à une population en particulier. Les Tsiganes ou les Roms, appelez-les comme vous voudrez, représentent environ une dizaine de millions d’individus en Europe. Cette population souvent stigmatisée et victime de persécutions, notamment à l’Est de notre Vieux Continent, paie un lourd tribut aux maladies génétiques du fait d’une forte endogamie. Dans ce contexte, les maladies neuromusculaires ne font pas exception. Elles sont fréquentes chez les Roms et souvent associées, pour certaines d’entre elles, à des mutations dites « privées ». Depuis une vingtaine d’années, un petit groupe de myologues européens s’intéresse à cette thématique, particulièrement en Bulgarie où, au-delà de la recherche académique, de réelles avancées ont pu être conduites en matière de prise en charge et de prévention. Chemin faisant, il a également été possible de confirmer l’origine géographique de ce peuple nomade et d’imaginer les modalités de ses migrations à travers le monde

157th ENMC International Workshop: Patient registries for rare, inherited muscular disorders 25–27 January 2008 Naarden, The Netherlands

International audienc

Neuromuscular junction involvement in inherited motor neuropathies: genetic heterogeneity and effect of oral salbutamol treatment.

Acknowledgements: R.H. is a Wellcome Trust Investigator (109915/Z/15/Z), who receives support from the Medical Research Council (UK) (MR/N025431/1 and MR/V009346/1), the European Research Council (309548), the Newton Fund (UK/Turkey, MR/N027302/1), the Addenbrookes Charitable Trust (G100142), the Evelyn Trust, the Stoneygate Trust, the Lily Foundation and an MRC strategic award to establish an International Centre for Genomic Medicine in Neuromuscular Diseases (ICGNMD) MR/S005021/1. RH is part of the PROSPAX consortium under the frame of EJP RD, the European Joint Programme on Rare Diseases, under the EJP RD COFUND-EJP N°825575. The study was further supported by the Horizon 2020 research and innovation program via grant 779257 “Solve-RD”. Data were analysed using the RD-Connect Genome-Phenome Analysis Platform developed under FP7/2007-2013 funded project (grant agreement nº 305444) and funding from European Joint Programme in Rare Disease (EJP-RD) and INB/ELIXIR-ES. This research was also supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. HL received support from the Newton Fund (UK/Turkey, MR/N027302/1), the Wellcome Trust Pathfinder Scheme (201064/Z/16/Z to HL and RH), the Canadian Institutes of Health Research (Foundation Grant FDN-167281), the Canadian Institutes of Health Research and Muscular Dystrophy Canada (Network Catalyst Grant for NMD4C), the Canada Foundation for Innovation (CFI-JELF 38412), and the Canada Research Chairs program (Canada Research Chair in Neuromuscular Genomics and Health, 950-232279).Funder: Evelyn Trust; doi: http://dx.doi.org/10.13039/501100004282Funder: Lily Foundation; doi: http://dx.doi.org/10.13039/501100022186OBJECTIVES: Inherited defects of the neuromuscular junction (NMJ) comprise an increasingly diverse range of diseases. Several recently identified genes highlight the overlap between peripheral neuropathies and congenital myasthenic syndromes (CMS). The beta-2 adrenergic receptor agonist salbutamol has been shown to provide symptomatic benefit in CMS, while improving structural defects at the NMJ. Based on these findings, we identified cases of motor neuropathy with NMJ dysfunction and assessed the effect of salbutamol on motor function. METHODS: Cases of motor neuropathy with significant NMJ dysfunction, were identified using repetitive nerve stimulation and single fibre electromyography. Oral salbutamol was administered for 12 months. Repeat neurophysiological and clinical assessments were undertaken at baseline, 6 months and 12 months. RESULTS: Significant defects of neuromuscular transmission were identified in 15 patients harbouring a range of genetic defects, including mutations in GARS1, DNM2, SYT2 and DYNC1H. No clear benefit on motor function was seen following the administration of 12 months of oral salbutamol; however, there was a significant improvement in patient reported fatigue. In addition, no clear effect on neurophysiological parameters was seen in patients treated with salbutamol. Side-effects due to off-target beta-adrenergic effects were significant in the patient cohort. CONCLUSION: These results highlight the involvement of the NMJ in several subtypes of motor neuropathies, including subtypes of neuropathy due to deficits in mitochondrial fusion-fission, synaptic vesicle transport, calcium channels and tRNA synthetases. Whether the NMJ dysfunction is simply due to muscle reinnervation or a pathology unrelated to denervation is unknown. The involvement of the NMJ may represent a novel therapeutic target in these conditions. However, treatment regimens will need to be more targeted for patients with primary inherited defects of neuromuscular transmission

Congenital Myasthenic Syndromes or Inherited Disorders of Neuromuscular Transmission: Recent Discoveries and Open Questions

International audienceCongenital myasthenic syndromes (CMS) form a heterogeneous group of rare diseases characterized by fatigable muscle weakness. They are genetically-inherited and caused by defective synaptic transmission at the cholinergic neuromus-cular junction (NMJ). The number of genes known to cause CMS when mutated is currently 30, and the relationship between fatigable muscle weakness and defective functions is quite well-understood for many of them. However, some of the most recent discoveries in individuals with CMS challenge our knowledge of the NMJ, where the basis of the pathology has mostly been investigated in animal models. Frontier forms between CMS and congenital myopathy, which have been genetically and clinically identified, underline the poorly understood interplay between the synaptic and extrasynaptic molecules in the neuromuscular system. In addition, precise electrophysiological and histopathological investigations of individuals with CMS suggest an important role of NMJ plasticity in the response to CMS pathogenesis. While efficient drug-based treatments are already available to improve neuromuscular transmission for most forms of CMS, others, as well as neurological and muscular comorbidities, remain resistant. Taken together, the available pathological data point to physiological issues which remain to be understood in order to achieve precision medicine with efficient therapeutics for all individuals suffering from CMS