The natural course of infantile Pompe's disease: 20 original cases compared with 133 cases from the literature

OBJECTIVE: Infantile Pompe's disease is a lethal cardiac and muscular disorder. Current developments toward enzyme replacement therapy are promising. The aim of our study is to delineate the natural course of the disease to verify endpoints of clinical studies. METHODS: A total of 20 infantile patients diagnosed by the collaborative Dutch centers and 133 cases reported in literature were included in the study. Information on clinical history, physical examination, and diagnostic parameters was collected. RESULTS: The course of Pompe's disease is essentially the same in the Dutch and the general patient population. Symptoms start at a median age of 1.6 months in both groups. The median age of death is 7.7 and 6 months, respectively. Five percent of the Dutch patients and 8% of all reported patients survive beyond 1 year of age. Only 2 patients from literature became older than 18 months. A progressive cardiac hypertrophy is characteristic for infantile Pompe's disease. The diastolic thickness of the left ventricular posterior wall and cardiac weight at autopsy increase significantly with age. Motor development is severely delayed and major d

Biodegradable Synthetic Organelles Demonstrate ROS Shielding in Human-Complex-I-Deficient Fibroblasts

Biodegradable, semipermeable nanoreactors that are capable of undergoing cellular integration and, subsequently, function as synthetic organelles represent an exciting therapeutic technology. Polymersomal nanoreactors have been investigated as a suitable candidate for the engineering of such a system, with the chemical versatility and structural robustness required for such a demanding application. Although steps have been taken to demonstrate this capacity, there has yet to be a system presented with biochemically robust data showing therapeutic efficacy in primary human cells. The reason for this shortfall is the absence of essential criteria of the polymersomes tested so far; biodegradability, intrinsic semipermeability, and a biomedically relevant setting. Herein, we present enzyme-loaded, biodegradable poly(ethylene glycol)-block-poly(caprolactone-gradient-trimethylene carbonate) (PEG-PCLgTMC) polymersomal nanoreactors, readily fabricated using the biocompatible direct hydration methodology. Physical characterization of PEG-PCLgTMC polymersomes highlights their semipermeable membrane and ability to shield enzymatic cargo. Surface modification with cell-penetrating peptides (CPPs) directs cellular integration of enzyme-loaded PEG-PCLgTMC nanoreactors in a controlled fashion. Using HEK293T cells and human skin fibroblasts we demonstrate that biocompatible catalase nanoreactors successfully perform as a synthetic organelle, imparting activity-dependent antioxidant (reactive-oxygen-species-shielding, ROS-shielding) capacity to cells. Notably, for the first time, patient-derived human-complex-I-deficient primary fibroblasts are effectively protected against the toxicity of exogenous H2O2 by the action of internalized enzyme-loaded nanoreactors, showcasing this system in a therapeutically relevant context

International Paediatric Mitochondrial Disease Scale

Objective: There is an urgent need for reliable and universally applicable outcome measures for children with mitochondrial diseases. In this study, we aimed to adapt the currently available Newcastle Paediatric Mitochondrial Disease Scale (NPMDS) to the International Paediatric Mitochondrial Disease Scale (IPMDS) during a Delphi-based process with input from international collaborators, patients and caretakers, as well as a pilot reliability study in eight patients. Subsequently, we aimed to test the feasibility, construct validity and reliability of the IPMDS in a multicentre study. Methods: A clinically, biochemically and genetically heterogeneous group of 17 patients (age 1.6–16 years) from five different expert centres from four different continents were evaluated in this study. Results: The feasibility of the IPMDS was good, as indicated by a low number of missing items (4 %) and the positive evaluation of patients, parents and users. Principal component analysis of our small sample identified three factors, which explained 57.9 % of the variance. Good construct validity was found using hypothesis testing. The overall interrater reliability was good [median intraclass correlation coefficient for agreement between raters (ICCagreement) 0.85; range 0.23–0.99). Conclusion: In conclusion, we suggest using the IPMDS for assessing natural history in children with mitochondrial diseases. These data should be used to further explore construct validity of the IPMDS and to set age limits. In parallel, responsiveness and the minimal clinically important difference should be studied to facilitate sample size calculations in future clinical trials

Long-term intravenous treatment of Pompe disease with recombinant human alpha-glucosidase from milk

OBJECTIVE: Recent reports warn that the worldwide cell culture capacity is insufficient to fulfill the increasing demand for human protein drugs. Production in milk of transgenic animals is an attractive alternative. Kilogram quantities of product per year can be obtained at relatively low costs, even in small animals such as rabbits. We tested the long-term safety and efficacy of recombinant human -glucosidase (rhAGLU) from rabbit milk for the treatment of the lysosomal storage disorder Pompe disease. The disease occurs with an estimated frequency of 1 in 40,000 and is designated as orphan disease. The classic infantile form leads to death at a median age of 6 to 8 months and is diagnosed by absence of alpha-glucosidase activity and presence of fully deleterious mutations in the alpha-glucosidase gene. Cardiac hypertrophy is characteristically present. Loss of muscle strength prevents infants from achieving developmental milestones such as sitting, standing, and walking. Milde

Mitochondrial Disease Sequence Data Resource (MSeqDR): A global grass-roots consortium to facilitate deposition, curation, annotation, and integrated analysis of genomic data for the mitochondrial disease clinical and research communities

Success rates for genomic analyses of highly heterogeneous disorders can be greatly improved if a large cohort of patient data is assembled to enhance collective capabilities for accurate sequence variant annotation, analysis, and interpretation. Indeed, molecular diagnostics requires the establishment of robust data resources to enable data sharing that informs accurate understanding of genes, variants, and phenotypes. The "Mitochondrial Disease Sequence Data Resource (MSeqDR) Consortium" is a grass-roots effort facilitated by the United Mitochondrial Disease Foundation to identify and prioritize specific genomic data analysis needs of the global mitochondrial disease clinical and research community. A central Web portal (. https://mseqdr.org) facilitates the coherent compilation, organization, annotation, and analysis of sequence data from both nuclear and mitochondrial genomes of individuals and families with suspected mitochondrial disease. This Web portal provides users with a flexible and expandable suite of resources to enable variant-, gene-, and exome-level sequence analysis in a secure, Web-based, and user-friendly fashion. Users can also elect to share data with other MSeqDR Consortium members, or even the general public, either by custom annotation tracks or through the use of a convenient distributed annotation system (DAS) mechanism. A range of data visualization and analysis tools are provided to facilitate user interrogation and understanding of genomic, and ultimately phenotypic, data of relevance to mitochondrial biology and disease. Currently available tools for nuclear and mitochondrial gene analyses include an MSeqDR GBrowse instance that hosts optimized mitochondrial disease and mitochondrial DNA (mtDNA) specific annotation tracks, as well as an MSeqDR locus-specific database (LSDB) that curates variant data on more than 1300 genes that have been implicated in mitochondrial disease and/or encode mitochondria-localized proteins. MSeqDR is integrated with a diverse array of mtDNA data analysis tools that are both freestanding and incorporated into an online exome-level dataset curation and analysis resource (GEM.app) that is being optimized to support needs of the MSeqDR community. In addition, MSeqDR supports mitochondrial disease phenotyping and ontology tools, and provides variant pathogenicity assessment features that enable community review, feedback, and integration with the public ClinVar variant annotation resource. A centralized Web-based informed consent process is being developed, with implementation of a Global Unique Identifier (GUID) system to integrate data deposited on a given individual from different sources. Community-based data deposition into MSeqDR has already begun. Future efforts will enhance capabilities to incorporate phenotypic data that enhance genomic data analyses. MSeqDR will fill the existing void in bioinformatics tools and centralized knowledge that are necessary to enable efficient nuclear and mtDNA genomic data interpretation by a range of shareholders across both clinical diagnostic and research settings. Ultimately, MSeqDR is focused on empowering the global mitochondrial disease community to better define and explore mitochondrial diseases