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Journal of Inherited Metabolic Disease Sep 2019Alpha-mannosidosis (OMIM 248500) is a rare lysosomal storage disorder caused by a deficiency of the enzyme alpha-mannosidase. Recently, enzyme replacement therapy was...
Alpha-mannosidosis (OMIM 248500) is a rare lysosomal storage disorder caused by a deficiency of the enzyme alpha-mannosidase. Recently, enzyme replacement therapy was approved in the European Union for the treatment of alpha-mannosidosis, but evaluation regarding long-term efficacy and safety is hard to assess due to missing quantitative natural history data, in particular survival. We performed a quantitative analysis of published cases (N = 111) with alpha-mannosidosis. Main outcome measures were age of disease onset, diagnostic delay and survival (overall and by subgroup exploration). Residual alpha-mannosidase activity and age of onset were explored as potential predictors of survival. STROBE criteria were respected. Median age of onset was 12 months. Median diagnostic delay was 6 years. At the age of 41 years 72.3% of patients were alive (N = 111). Residual alpha-mannosidase activity (N = 34) predicted survival: Patients with a residual alpha-mannosidase activity below or equal to 4.5% of normal in fibroblasts had a median survival of 3.5 years, whereas patients with alpha-mannosidase activity above this threshold all survived during the observation period reported. Patients with age of onset above 7 years survived significantly longer than patients with age of onset below or equal to 7 years. Patient distribution was panethnic with hotspots in the United States and Germany. We defined age of onset, diagnostic delay, and survival characteristics in a global cohort of 111 patients with alpha-mannosidosis by retrospective quantitative natural history modeling. These data expand the quantitative understanding of the clinical phenotype.
Topics: Adolescent; Adult; Age of Onset; Biomarkers; Child; Child, Preschool; Cross-Sectional Studies; Delayed Diagnosis; Enzyme Replacement Therapy; Female; Humans; Infant; Male; Phenotype; Retrospective Studies; Survival Analysis; Young Adult; alpha-Mannosidosis
PubMed: 31222755
DOI: 10.1002/jimd.12138 -
Chemphyschem : a European Journal of... Dec 2023The catalytic mechanism of a -dependent family 92 -mannosidase, which is abundantly present in human gut flora and malfunctions leading to the lysosomal storage...
The catalytic mechanism of a -dependent family 92 -mannosidase, which is abundantly present in human gut flora and malfunctions leading to the lysosomal storage disease α-mannosidosis, has been investigated using quantum mechanics/molecular mechanics and metadynamics methods. Computational efforts show that the enzyme follows a conformational itinerary of and the ion serves a dual purpose, as it not only distorts the sugar ring but also plays a crucial role in orchestrating the arrangement of catalytic residues. This orchestration, in turn, contributes to the facilitation of conformers for the ensuing reaction. This mechanistic insight is well-aligned with the experimental predictions of the catalytic pathway, and the computed energies are of the same order of magnitude as the experimental estimations. Hence, our results extend the mechanistic understanding of glycosidases.
Topics: Catalysis; Mannosidases; Molecular Conformation; Molecular Dynamics Simulation; Gastrointestinal Microbiome; alpha-Mannosidosis; Bacterial Proteins
PubMed: 37782219
DOI: 10.1002/cphc.202300628 -
Cureus Apr 2024Alpha-mannosidosis is a rare lysosomal storage disorder with progressive impairments in motor functions, skeletal deformities, and immunodeficiency. Enzyme replacement...
Prenatal Diagnosis of c.437-1G>A Mutation in the MAN2B1 Gene in a Family With Alpha-Mannosidosis: Unraveling Clinical Presentation and Treatment Outcomes in a Novel Prenatal Case.
Alpha-mannosidosis is a rare lysosomal storage disorder with progressive impairments in motor functions, skeletal deformities, and immunodeficiency. Enzyme replacement therapy (ERT) should be initiated early to achieve optimal outcomes. This report describes how alpha-mannosidosis diagnosis in a seven-year-old girl led to a successful prenatal diagnosis in the subsequent pregnancy and pre-symptomatic treatment at the early disease stage. The index patient was a seven-year-old girl who was referred with a confirmed diagnosis of alpha-mannosidosis based on the presence of homozygous c.437-1G>A mutation in the MAN2B1 gene. A prenatal diagnosis was made in the subsequent pregnancy through molecular analysis, which revealed the same homozygous variant. The patient was treated at the fifth week of age and showed mild skeletal involvement and normal development at ERT initiation. At 11 months of age, the ERT level increased to 15.8 µmol/l/h. The motor assessment showed that the patient was developmentally normal and was able to maintain her sitting and walking for a few steps only. Prenatal molecular screening in affected families can allow for the early identification and implementation of appropriate management strategies for alpha-mannosidosis.
PubMed: 38800253
DOI: 10.7759/cureus.58922 -
Italian Journal of Pediatrics Sep 2019Procedural sedation is increasingly needed in pediatrics. Although different drugs or drugs association are available, which is the safest and most efficient has yet to...
BACKGROUND
Procedural sedation is increasingly needed in pediatrics. Although different drugs or drugs association are available, which is the safest and most efficient has yet to be defined, especially in syndromic children with increased sedation-related risk factors.
CASE REPORT
we report the case of a five-year-old child affected by alpha-mannosidosis who required procedural sedation for an MRI scan and a lumbar puncture. We administered intranasal dexmedetomidine (4 μg/kg) 45 min before intravenous cannulation, followed by one bolus of ketamine (1 mg/kg) for each procedure. The patient maintained spontaneous breathing and no desaturation or any complication occurred.
CONCLUSION
intranasal dexmedetomidine and intravenous ketamine could be a feasible option for MRI and lumbar puncture in children with alpha-mannosidosis needing sedation.
Topics: Administration, Intranasal; Anesthetics, Dissociative; Child, Preschool; Dexmedetomidine; Humans; Hypnotics and Sedatives; Infusions, Intravenous; Ketamine; Magnetic Resonance Imaging; Male; Spinal Puncture; alpha-Mannosidosis
PubMed: 31481093
DOI: 10.1186/s13052-019-0711-1 -
Orphanet Journal of Rare Diseases Jan 2021Oligosaccharidoses are storage disorders due to enzymatic defects involved in the breakdown of the oligosaccharidic component of glycosylated proteins. The defect cause...
BACKGROUND
Oligosaccharidoses are storage disorders due to enzymatic defects involved in the breakdown of the oligosaccharidic component of glycosylated proteins. The defect cause the accumulation of oligosaccharides (OS) and, depending on the lacking enzyme, results in characteristic profiles which are helpful for the diagnosis. We developed a new tandem mass spectrometry method for the screening of urinary OS which was applied to identify a large panel of storage disorders.
METHODS
The method was set-up in urine and dried urine spots (DUS). Samples were analysed, without derivatization and using maltoheptaose as internal standard, by UHPLC-MS/MS with MRM acquisition of target OS transitions, including Glc4, the biomarker of Pompe disease. The chromatographic run was < 30 min. Samples from patients with known storage disorders were used for clinical validation.
RESULTS
The method allowed to confirm the diagnosis of oligosaccharidoses (sialidosis, α-/β-mannosidosis, fucosidosis, aspartylglucosaminuria) and of GM1 and GM2 (Sandhoff type) gangliosidosis, by detecting specific OS profiles. In other storage disorders (mucolipidosis II and III, mucopolysaccharidosis type IVB) the analyisis revealed abnormal OS excretion with non-specific profiles. Besides Pompe disease, the tetrasaccharide Glc4 was increased also in disorders of autophagy (Vici syndrome, Yunis-Varon syndrome, and Danon disease) presenting cardiomuscular involvement with glycogen storage. Overall, results showed a clear separation between patients and controls, both in urine and in DUS.
CONCLUSION
This new UHPLC/MS-MS method, which is suitable for rapid and easy screening of OS in urine and DUS, expands the detection of storage disorders from oligosaccharidoses to other diseases, including the novel category of inherited disorders of autophagy.
Topics: Chromatography, High Pressure Liquid; Fucosidosis; Glycogen Storage Disease Type II; Humans; Lysosomal Storage Diseases; Oligosaccharides; Tandem Mass Spectrometry
PubMed: 33422100
DOI: 10.1186/s13023-020-01662-8 -
Brain : a Journal of Neurology Jul 2020Intravascular injection of certain adeno-associated virus vector serotypes can cross the blood-brain barrier to deliver a gene into the CNS. However, gene distribution...
Intravascular injection of certain adeno-associated virus vector serotypes can cross the blood-brain barrier to deliver a gene into the CNS. However, gene distribution has been much more limited within the brains of large animals compared to rodents, rendering this approach suboptimal for treatment of the global brain lesions present in most human neurogenetic diseases. The most commonly used serotype in animal and human studies is 9, which also has the property of being transported via axonal pathways to distal neurons. A small number of other serotypes share this property, three of which were tested intravenously in mice compared to 9. Serotype hu.11 transduced fewer cells in the brain than 9, rh8 was similar to 9, but hu.32 mediated substantially greater transduction than the others throughout the mouse brain. To evaluate the potential for therapeutic application of the hu.32 serotype in a gyrencephalic brain of larger mammals, a hu.32 vector expressing the green fluorescent protein reporter gene was evaluated in the cat. Transduction was widely distributed in the cat brain, including in the cerebral cortex, an important target since mental retardation is an important component of many of the human neurogenetic diseases. The therapeutic potential of a hu.32 serotype vector was evaluated in the cat homologue of the human lysosomal storage disease alpha-mannosidosis, which has globally distributed lysosomal storage lesions in the brain. Treated alpha-mannosidosis cats had reduced severity of neurological signs and extended life spans compared to untreated cats. The extent of therapy was dose dependent and intra-arterial injection was more effective than intravenous delivery. Pre-mortem, non-invasive magnetic resonance spectroscopy and diffusion tensor imaging detected differences between the low and high doses, and showed normalization of grey and white matter imaging parameters at the higher dose. The imaging analysis was corroborated by post-mortem histological analysis, which showed reversal of histopathology throughout the brain with the high dose, intra-arterial treatment. The hu.32 serotype would appear to provide a significant advantage for effective treatment of the gyrencephalic brain by systemic adeno-associated virus delivery in human neurological diseases with widespread brain lesions.
Topics: Animals; Brain; Cats; Dependovirus; Disease Models, Animal; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Transduction, Genetic; alpha-Mannosidosis
PubMed: 32671406
DOI: 10.1093/brain/awaa161 -
Journal of Pediatric Neurosciences 2021Alpha-mannosidosis is a lysosomal storage disorder caused by mutations in gene. A 7-year-old girl child, born of a consanguineous marriage, presented with developmental...
Alpha-mannosidosis is a lysosomal storage disorder caused by mutations in gene. A 7-year-old girl child, born of a consanguineous marriage, presented with developmental delay, seizures, and hearing impairment. On examination, she had coarse features without hepatosplenomegaly. On investigations, low levels of the enzyme alpha-mannosidase level were observed. Targeted next-generation sequencing revealed a novel pathogenic variant p.Trp469Ter on exon 11 of gene.
PubMed: 36160623
DOI: 10.4103/jpn.JPN_71_20 -
Pediatric Pulmonology Apr 2023
Topics: Humans; beta-Mannosidosis; alpha-Mannosidosis; Hemorrhage
PubMed: 36610029
DOI: 10.1002/ppul.26310 -
Journal of the American Chemical Society Jul 2020Golgi mannosidase II (GMII) catalyzes the sequential hydrolysis of two mannosyl residues from GlcNAcManGlcNAc to produce GlcNAcManGlcNAc, the precursor for all complex...
Golgi mannosidase II (GMII) catalyzes the sequential hydrolysis of two mannosyl residues from GlcNAcManGlcNAc to produce GlcNAcManGlcNAc, the precursor for all complex -glycans, including the branched -glycans associated with cancer. Inhibitors of GMII are potential cancer therapeutics, but their usefulness is limited by off-target effects, which produce α-mannosidosis-like symptoms. Despite many structural and mechanistic studies of GMII, we still lack a potent and selective inhibitor of this enzyme. Here, we synthesized manno--cyclophellitol epoxide and aziridines and demonstrate their covalent modification and time-dependent inhibition of GMII. Application of fluorescent manno--cyclophellitol aziridine derivatives enabled activity-based protein profiling of α-mannosidases from both human cell lysate and mouse tissue extracts. Synthesized probes also facilitated a fluorescence polarization-based screen for dGMII inhibitors. We identified seven previously unknown inhibitors of GMII from a library of over 350 iminosugars and investigated their binding modalities through X-ray crystallography. Our results reveal previously unobserved inhibitor binding modes and promising scaffolds for the generation of selective GMII inhibitors.
Topics: Cyclohexanols; Drug Discovery; Enzyme Inhibitors; Humans; Mannosidases; Molecular Structure
PubMed: 32605368
DOI: 10.1021/jacs.0c03880 -
Genes Aug 2023A 7-month-old Doberman Pinscher dog presented with progressive neurological signs and brain atrophy suggestive of a hereditary neurodegenerative disorder. The dog was...
A Homozygous Missense Mutation in a Doberman Pinscher Dog with Neurodegeneration, Cytoplasmic Vacuoles, Autofluorescent Storage Granules, and an α-Mannosidase Deficiency.
A 7-month-old Doberman Pinscher dog presented with progressive neurological signs and brain atrophy suggestive of a hereditary neurodegenerative disorder. The dog was euthanized due to the progression of disease signs. Microscopic examination of tissues collected at the time of euthanasia revealed massive accumulations of vacuolar inclusions in cells throughout the central nervous system, suggestive of a lysosomal storage disorder. A whole genome sequence generated with DNA from the affected dog contained a likely causal, homozygous missense variant in that predicted an Asp104Gly amino acid substitution that was unique among whole genome sequences from over 4000 dogs. A lack of detectable α-mannosidase enzyme activity confirmed a diagnosis of a-mannosidosis. In addition to the vacuolar inclusions characteristic of α-mannosidosis, the dog exhibited accumulations of autofluorescent intracellular inclusions in some of the same tissues. The autofluorescence was similar to that which occurs in a group of lysosomal storage disorders called neuronal ceroid lipofuscinoses (NCLs). As in many of the NCLs, some of the storage bodies immunostained strongly for mitochondrial ATP synthase subunit c protein. This protein is not a substrate for α-mannosidase, so its accumulation and the development of storage body autofluorescence were likely due to a generalized impairment of lysosomal function secondary to the accumulation of α-mannosidase substrates. Thus, it appears that storage body autofluorescence and subunit c accumulation are not unique to the NCLs. Consistent with generalized lysosomal impairment, the affected dog exhibited accumulations of intracellular inclusions with varied and complex ultrastructural features characteristic of autophagolysosomes. Impaired autophagic flux may be a general feature of this class of disorders that contributes to disease pathology and could be a target for therapeutic intervention. In addition to storage body accumulation, glial activation indicative of neuroinflammation was observed in the brain and spinal cord of the proband.
Topics: Animals; Dogs; alpha-Mannosidase; alpha-Mannosidosis; Lysosomal Storage Diseases; Lysosomes; Mutation, Missense; Vacuoles; Neurodegenerative Diseases
PubMed: 37761886
DOI: 10.3390/genes14091746