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)

Heterozygous frameshift variants in HNRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy

Missense variants in RNA-binding proteins (RBPs) underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, and inclusion body myopathy. Here, we present ten independent families with a severe, progressive muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD) but of much earlier onset, caused by heterozygous frameshift variants in the RBP hnRNPA2/B1. All disease-causing frameshift mutations abolish the native stop codon and extend the reading frame, creating novel transcripts that escape nonsense-mediated decay and are translated to produce hnRNPA2/B1 protein with the same neomorphic C-terminal sequence. In contrast to previously reported disease-causing missense variants in HNRNPA2B1, these frameshift variants do not increase the propensity of hnRNPA2 protein to fibrillize. Rather, the frameshift variants have reduced affinity for the nuclear import receptor karyopherin β2, resulting in cytoplasmic accumulation of hnRNPA2 protein in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with HNRNPA2B1 to include an early-onset form of OPMD caused by frameshift variants that alter its nucleocytoplasmic transport dynamics

Eight years after an international workshop on myotonic dystrophy patient registries: case study of a global collaboration for a rare disease.

Background Myotonic Dystrophy is the most common form of muscular dystrophy in adults, affecting an estimated 10 per 100,000 people. It is a multisystemic disorder affecting multiple generations with increasing severity. There are currently no licenced therapies to reverse, slow down or cure its symptoms. In 2009 TREAT-NMD (a global alliance with the mission of improving trial readiness for neuromuscular diseases) and the Marigold Foundation held a workshop of key opinion leaders to agree a minimal dataset for patient registries in myotonic dystrophy. Eight years after this workshop, we surveyed 22 registries collecting information on myotonic dystrophy patients to assess the proliferation and utility the dataset agreed in 2009. These registries represent over 10,000 myotonic dystrophy patients worldwide (Europe, North America, Asia and Oceania). Results The registries use a variety of data collection methods (e.g. online patient surveys or clinician led) and have a variety of budgets (from being run by volunteers to annual budgets over €200,000). All registries collect at least some of the originally agreed data items, and a number of additional items have been suggested in particular items on cognitive impact. Conclusions The community should consider how to maximise this collective resource in future therapeutic programmes

Are Peripheral Blood Mononuclear Cells Derived from Patients with Certain Myopathies Suitable for Personalized Drug Screening?

Background: Limb girdle muscular dystrophies (LGMDs) and several other disorders which share their specific phenotype are rare, predominantly hereditary conditions with no curative treatment. Differential diagnosis of these myopathies is quite challenging and expensive in many cases. Therefore, a significant proportion of patients remains undiagnosed and untreated for a long time. At the same time there is a huge amount of drugs and supplements potentially able to modify the course of some of these muscular dystrophies. That is why a simple empirical approach able to define a patient’s reaction to a specific compound seems rational. Because most common basic pathogenetic mechanisms for these quite different disorders increase the vulnerability of muscle cells (or decrease ability for reparation) during mechanical stress, we propose a simple, noninvasive and inexpensive approach for individualized drug screening based on the drug’s influence on the mechanical vulnerability of peripheral blood mononuclear cells (PBMC). Methods: PBMC derived from 8 patients with Duchenne muscular dystrophy (DMD), 2 patients with LGMD2A, 1 patient with LGMD2B, 1 with MERRF syndrome, 1 with facioscapulohumeral muscular dystrophy (FSHD) and 13 matched control subjects were irradiated by ultrasound in the presence of several compounds (lisinopril, vitamin D3, prednisolon, tocopherol, topiramate, glutargin, α-lipoic acid, essentiale, and physiological solution). Then viability indexes of the samples were detected by citotoxic assays based on vital dye (neutral red and resazurin) metabolism. Results: In cytotoxicity tests with active transport of neutral red into PBMC derived from DMD patients, the cells showed signs of destruction at 1.06±0.52 minutes of ultrasounding compared to 1.75±0.6 minutes in control. PBMCs from patients with other myopathies have either normal or decreased resistance to ultrasound. The addition of tocopherol significantly changes the PBMC time-destruction curves; however, these changes as well as changes caused by other compounds were inconclusive concerning their protective effects. In resazurin cytotoxicity tests, PBMC metabolic activity normalized to 0.9% NaCl in the presence of tested compounds differed significantly in experiments with and without ultrasounding. Also, profiles of the compounds’ protective effects were very dissimilar in patients with different myopathies. Conclusion: We believe that peculiarities of PBCM behavior after US stress in the presence of different compounds are reliable patient-specific phenomena, which warrant further investigation and a proposed approach worth further improvement

Ethnicity-related DMD Genotype Landscapes in European and Non-European Countries

Objective Genetic diagnosis and mutation identification are now compulsory for Duchenne (DMD) and Becker muscular dystrophies (BMD), which are due to dystrophin (DMD) gene mutations, either for disease prevention or personalized therapies. To evaluate the ethnic-related genetic assortments of DMD mutations, which may impact on DMD genetic diagnosis pipelines, we studied 328 patients with DMD and BMD from non-European countries. Methods We performed a full DMD mutation detection in 328 patients from 10 Eastern European countries (Poland, Hungary, Lithuania, Romania, Serbia, Croatia, Bosnia, Bulgaria, Ukraine,and Russia) and 2 non-European countries (Cyprus and Algeria). We used both conventional methods (multiplex ligation-dependent probe amplification [MLPA] followed by gene-specific sequencing) and whole-exome sequencing (WES) as a pivotal study ran in 28 patients where DMD mutations were already identified by standard techniques. WES output was also in-terrogated forDMDgene modifiers. Results We identified DMD gene mutations in 222 male patients. We identified a remarkable allele heterogeneity among different populations with a mutation landscape often country specific. We also showed that WES is effective for picking up all DMD deletions and small mutations and its adoption could allow a detection rate close to 90% of all occurring mutations. Gene modifiers haplotypes were identified with some ethnic-specific configurations. Conclusions Our data provide unreported mutation landscapes in different countries, suggesting that ethnicity may orient genetic diagnosis flowchart, which can be adjusted depending on the mutation type frequency, with impact in drug eligibility

The TREAT-NMD Duchenne Muscular Dystrophy Registries: Conception, Design, and Utilization by Industry and Academia.

Duchenne muscular dystrophy (DMD) is an X-linked genetic disease, caused by the absence of the dystrophin protein. Although many novel therapies are under development for DMD, there is currently no cure and affected individuals are often confined to a wheelchair by their teens and die in their twenties/thirties. DMD is a rare disease (prevalence <5/10,000). Even the largest countries do not have enough affected patients to rigorously assess novel therapies, unravel genetic complexities, and determine patient outcomes. TREAT-NMD is a worldwide network for neuromuscular diseases that provides an infrastructure to support the delivery of promising new therapies for patients. The harmonized implementation of national and ultimately global patient registries has been central to the success of TREAT-NMD. For the DMD registries within TREAT-NMD, individual countries have chosen to collect patient information in the form of standardized patient registries to increase the overall patient population on which clinical outcomes and new technologies can be assessed. The registries comprise more than 13,500 patients from 31 different countries. Here, we describe how the TREAT-NMD national patient registries for DMD were established. We look at their continued growth and assess how successful they have been at fostering collaboration between academia, patient organizations, and industry

Correction to: Eight years after an international workshop on myotonic dystrophy patient registries: case study of a global collaboration for a rare disease

The original version of this article [1] unfortunately included an error to an author’s name. Author Jordi Díaz-Manera was erroneously presented as Jorge Alberto Diaz Manera. The correct author name has been included in the author list of this Correction article

Heterozygous frameshift variants in HNRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy.

Funder: Howard Hughes Medical InstituteMissense variants in RNA-binding proteins (RBPs) underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, and inclusion body myopathy. Here, we present ten independent families with a severe, progressive muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD) but of much earlier onset, caused by heterozygous frameshift variants in the RBP hnRNPA2/B1. All disease-causing frameshift mutations abolish the native stop codon and extend the reading frame, creating novel transcripts that escape nonsense-mediated decay and are translated to produce hnRNPA2/B1 protein with the same neomorphic C-terminal sequence. In contrast to previously reported disease-causing missense variants in HNRNPA2B1, these frameshift variants do not increase the propensity of hnRNPA2 protein to fibrillize. Rather, the frameshift variants have reduced affinity for the nuclear import receptor karyopherin β2, resulting in cytoplasmic accumulation of hnRNPA2 protein in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with HNRNPA2B1 to include an early-onset form of OPMD caused by frameshift variants that alter its nucleocytoplasmic transport dynamics

Specific heterozygous frameshift variants hnRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy

RNA-binding proteins (RBPs) are essential for post-transcriptional regulation and processing of RNAs. Pathogenic missense variants in RBPs underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, inclusion body myopathy, distal myopathy, and Paget’s disease of the bone. Here, we present ten independent families with a severe, progressive, early-onset muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD), caused by heterozygous frameshift variants in the prion-like domain of hnRNPA2B1. We found that in contrast with the previously reported missense variants, the frameshift hnRNPA2B1 variants do not promote, but rather decelerate the fibrillization of the protein. Importantly, the frameshift variants harbor altered nuclear-localization sequences and exhibit reduced affinity for the nuclear-import receptor, Karyopherin-b2, which promotes their cytoplasmic accumulation in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with hnRNPA2B1 to include a severe, early-onset disease reminiscent of OPMD, caused by a distinct class of frameshift variants that alter its nucleocytoplasmic transport dynamics

Heterozygous frameshift variants in HNRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy

none58: Missense variants in RNA-binding proteins (RBPs) underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, and inclusion body myopathy. Here, we present ten independent families with a severe, progressive muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD) but of much earlier onset, caused by heterozygous frameshift variants in the RBP hnRNPA2/B1. All disease-causing frameshift mutations abolish the native stop codon and extend the reading frame, creating novel transcripts that escape nonsense-mediated decay and are translated to produce hnRNPA2/B1 protein with the same neomorphic C-terminal sequence. In contrast to previously reported disease-causing missense variants in HNRNPA2B1, these frameshift variants do not increase the propensity of hnRNPA2 protein to fibrillize. Rather, the frameshift variants have reduced affinity for the nuclear import receptor karyopherin β2, resulting in cytoplasmic accumulation of hnRNPA2 protein in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with HNRNPA2B1 to include an early-onset form of OPMD caused by frameshift variants that alter its nucleocytoplasmic transport dynamics.noneKim, Hong Joo; Mohassel, Payam; Donkervoort, Sandra; Guo, Lin; O'Donovan, Kevin; Coughlin, Maura; Lornage, Xaviere; Foulds, Nicola; Hammans, Simon R; Foley, A Reghan; Fare, Charlotte M; Ford, Alice F; Ogasawara, Masashi; Sato, Aki; Iida, Aritoshi; Munot, Pinki; Ambegaonkar, Gautam; Phadke, Rahul; O'Donovan, Dominic G; Buchert, Rebecca; Grimmel, Mona; Töpf, Ana; Zaharieva, Irina T; Brady, Lauren; Hu, Ying; Lloyd, Thomas E; Klein, Andrea; Steinlin, Maja; Kuster, Alice; Mercier, Sandra; Marcorelles, Pascale; Péréon, Yann; Fleurence, Emmanuelle; Manzur, Adnan; Ennis, Sarah; Upstill-Goddard, Rosanna; Bello, Luca; Bertolin, Cinzia; Pegoraro, Elena; Salviati, Leonardo; French, Courtney E; Shatillo, Andriy; Raymond, F Lucy; Haack, Tobias B; Quijano-Roy, Susana; Böhm, Johann; Nelson, Isabelle; Stojkovic, Tanya; Evangelista, Teresinha; Straub, Volker; Romero, Norma B; Laporte, Jocelyn; Muntoni, Francesco; Nishino, Ichizo; Tarnopolsky, Mark A; Shorter, James; Bönnemann, Carsten G; Taylor, J PaulKim, Hong Joo; Mohassel, Payam; Donkervoort, Sandra; Guo, Lin; O'Donovan, Kevin; Coughlin, Maura; Lornage, Xaviere; Foulds, Nicola; Hammans, Simon R; Foley, A Reghan; Fare, Charlotte M; Ford, Alice F; Ogasawara, Masashi; Sato, Aki; Iida, Aritoshi; Munot, Pinki; Ambegaonkar, Gautam; Phadke, Rahul; O'Donovan, Dominic G; Buchert, Rebecca; Grimmel, Mona; Töpf, Ana; Zaharieva, Irina T; Brady, Lauren; Hu, Ying; Lloyd, Thomas E; Klein, Andrea; Steinlin, Maja; Kuster, Alice; Mercier, Sandra; Marcorelles, Pascale; Péréon, Yann; Fleurence, Emmanuelle; Manzur, Adnan; Ennis, Sarah; Upstill-Goddard, Rosanna; Bello, Luca; Bertolin, Cinzia; Pegoraro, Elena; Salviati, Leonardo; French, Courtney E; Shatillo, Andriy; Raymond, F Lucy; Haack, Tobias B; Quijano-Roy, Susana; Böhm, Johann; Nelson, Isabelle; Stojkovic, Tanya; Evangelista, Teresinha; Straub, Volker; Romero, Norma B; Laporte, Jocelyn; Muntoni, Francesco; Nishino, Ichizo; Tarnopolsky, Mark A; Shorter, James; Bönnemann, Carsten G; Taylor, J Pau