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Frontiers in Bioscience (Landmark... Jan 2017Lysosomal alpha-mannosidase with acidic pH optimum is ubiquitous in human tissues where is expressed in two major forms, A and B that are the product of a single gene... (Review)
Review
Lysosomal alpha-mannosidase with acidic pH optimum is ubiquitous in human tissues where is expressed in two major forms, A and B that are the product of a single gene located on chromosome 19. Mutations in the gene encoding for alpha-mannosidase cause alpha- mannosidosis, an autosomal recessive disease, resulting in the accumulation of unprocessed mannose containing oligosaccharide material. This rare disease has an estimated incidence of 1/500.0.00 live births and clinically is divided into three subgroups. Today the most promising therapy for this disease is the enzyme replacement therapy. To develop this strategy a mouse model for alpha-mannosidosis has been generated and a recombinant human alpha-mannosidase has been produced from Chinese-hamster ovary cells. Interestingly it has been shown that the recombinant enzyme, used in high dose, can cross the blood brain barrier. This recombinant enzyme has been tested in the first randomized study investigating the efficacy of enzyme replacement therapy in patients with alpha-mannosidosis. This review contains the scientific progresses on lysosomal alpha-mannosidase from the cloning to the beginning of the therapy.
Topics: Animals; Disease Models, Animal; Enzyme Replacement Therapy; Humans; Lysosomes; Mutation; Recombinant Proteins; alpha-Mannosidase; alpha-Mannosidosis
PubMed: 27814608
DOI: 10.2741/4478 -
International Journal of Molecular... May 2018Alpha-mannosidosis (α-mannosidosis) is a rare lysosomal storage disorder with an autosomal recessive inheritance caused by mutations in the gene encoding for the... (Review)
Review
Alpha-mannosidosis (α-mannosidosis) is a rare lysosomal storage disorder with an autosomal recessive inheritance caused by mutations in the gene encoding for the lysosomal α-d-mannosidase. So far, 155 variants from 191 patients have been identified and in part characterized at the biochemical level. Similarly to other lysosomal storage diseases, there is no relationship between genotype and phenotype in alpha-mannosidosis. Enzyme replacement therapy is at the moment the most effective therapy for lysosomal storage disease, including alpha-mannosidosis. In this review, the genetic of alpha-mannosidosis has been described together with the results so far obtained by two different therapeutic strategies: bone marrow transplantation and enzyme replacement therapy. The primary indication to offer hematopoietic stem cell transplantation in patients affected by alpha-mannosidosis is preservation of neurocognitive function and prevention of early death. The results obtained from a Phase I⁻II study and a Phase III study provide evidence of the positive clinical effect of the recombinant enzyme on patients with alpha-mannosidosis.
Topics: Animals; Bone Marrow Transplantation; Combined Modality Therapy; Enzyme Activation; Enzyme Replacement Therapy; Genetic Association Studies; Humans; Mutation; alpha-Mannosidase; alpha-Mannosidosis
PubMed: 29772816
DOI: 10.3390/ijms19051500 -
Orphanet Journal of Rare Diseases Jul 2022Alpha-mannosidosis is a rare autosomal recessive lysosomal storage disorder (LSD) caused by reduced activity of alpha-mannosidase. Clinical manifestations include... (Review)
Review
BACKGROUND
Alpha-mannosidosis is a rare autosomal recessive lysosomal storage disorder (LSD) caused by reduced activity of alpha-mannosidase. Clinical manifestations include skeletal dysmorphism, mental impairment, hearing loss and recurrent infections. The severe type of the disease leads to early childhood death, while patients with milder forms can live into adulthood. There are no mortality studies to date. This study aimed to investigate the age at death and the causes of death of patients with alpha-mannosidosis who had not received disease-modifying treatment.
METHODS
Clinicians and LSD patient organisations (POs) from 33 countries were invited to complete a questionnaire between April-May 2021. Cause of death and age at death was available for 15 patients. A literature review identified seven deceased patients that met the inclusion criteria.
RESULTS
Median age at death for patients reported by clinicians/POs was 45 years (mean 40.3 ± 13.2, range 18-56, n = 15); 53% were female. One death occurred during the patient's second decade of life, and 14 out of 15 deaths (93.3%) during or after the patients' third decade, including four (26.7%) during their sixth decade. Median age at death for patients identified from the literature was 4.3 years (mean 15.7 ± 17.0, range 2.2-41, n = 7); two were female. Four of the seven patients (57.1%) died within the first decade of life. Seven of 15 deaths (46.7%) reported by clinicians/POs were recorded as pneumonia and three (20.0%) as cancer. Other causes of death included acute renal failure due to sepsis after intestinal perforation, decrease of red blood cells of unknown origin, kidney failure with systemic lupus erythematosus, aortic valve insufficiency leading to heart failure, and dehydration due to catatonia. Three out of seven causes of death (42.9%) reported in the literature were associated with septicaemia, two (28.6%) with respiratory failure and one to pneumonia following aspiration.
CONCLUSIONS
This study suggests that pneumonia has been the primary cause of death during recent decades in untreated patients with alpha-mannosidosis, followed by cancer. Determining the causes of mortality and life expectancy in these patients is crucial to further improve our understanding of the natural history of alpha-mannosidosis.
Topics: Adult; Child, Preschool; Female; Humans; Male; Middle Aged; alpha-Mannosidase; alpha-Mannosidosis; Hearing Loss; Intellectual Disability
PubMed: 35871018
DOI: 10.1186/s13023-022-02422-6 -
Orphanet Journal of Rare Diseases Jul 2008Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual... (Review)
Review
Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are immune deficiency (manifested by recurrent infections, especially in the first decade of life), skeletal abnormalities (mild-to-moderate dysostosis multiplex, scoliosis and deformation of the sternum), hearing impairment (moderate-to-severe sensorineural hearing loss), gradual impairment of mental functions and speech, and often, periods of psychosis. Associated motor function disturbances include muscular weakness, joint abnormalities and ataxia. The facial trait include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, and prognathism. Slight strabismus is common. The clinical variability is significant, representing a continuum in severity. The disorder is caused by lysosomal alpha-mannosidase deficiency. Alpha-mannosidosis is inherited in an autosomal recessive fashion and is caused by mutations in the MAN2B1 gene located on chromosome 19 (19 p13.2-q12). Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells and can be confirmed by genetic testing. Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic. Differential diagnoses are mainly the other lysosomal storage diseases like the mucopolysaccharidoses. Genetic counseling should be given to explain the nature of the disease and to detect carriers. Antenatal diagnosis is possible, based on both biochemical and genetic methods. The management should be pro-active, preventing complications and treating manifestations. Infections must be treated frequently. Otolaryngological treatment of fluid in the middle ear is often required and use of hearing aids is invariably required. Early educational intervention for development of social skills is needed and physiotherapy is important to improve bodily function. Orthopedic surgery may be necessary. The long-term prognosis is poor. There is an insidiously slow progression of neuromuscular and skeletal deterioration over several decades, making most patients wheel-chair dependent. No patients manage to be completely socially independent. Many patients are over 50 years of age.
Topics: Diagnosis, Differential; Genetic Counseling; Humans; Models, Molecular; Mutation; Prognosis; Protein Conformation; alpha-Mannosidase; alpha-Mannosidosis
PubMed: 18651971
DOI: 10.1186/1750-1172-3-21 -
Orphanet Journal of Rare Diseases Jun 2018α-mannosidosis is a rare, autosomal-recessive, lysosomal storage disease caused by a deficient activity of α-mannosidase. Typical symptoms include intellectual, motor...
BACKGROUND
α-mannosidosis is a rare, autosomal-recessive, lysosomal storage disease caused by a deficient activity of α-mannosidase. Typical symptoms include intellectual, motor and hearing impairment, facial coarsening, and musculoskeletal abnormalities. Ocular pathologies reported previously were mainly opacities of the cornea and lens, strabismus, and ocular motility disorders. However, retinal and optic nerve degeneration have been rarely described.
METHODS
We report ocular findings of 32 patients with α-mannosidosis. We particularly concentrated on retinal abnormalities which we supported by posterior segment examination, fundus photography, and Spectral-Domain optical coherence tomography (SD-OCT) imaging.
RESULTS
Tapeto-retinal degeneration with bone spicule formations in the peripheral retina or macular changes were seen in three patients (9.4%) on funduscopy; of these, two with optic nerve atrophy. Eight retinal images could be obtained by OCT or fundus photography; of these, six showed thinning of the outer retinal layers on OCT. Overall, optic nerve atrophy was seen in six patients (18.8%); of these, four with partial atrophy. Two patients had partial optic nerve atrophy with no retinal abnormalities on funduscopy. Cataract was seen in two (6.3%), corneal haze also in two patients (6.3%). Six patients (18.8%) had manifest strabismus, four (12.5%) nystagmus, and in five patients (15.6%) impaired smooth pursuit eye movements were seen.
CONCLUSION
Ocular pathologies are not exclusively confined to opacities of the cornea and lens or strabismus and ocular motility disorders but tapeto-retinal degeneration and optic nerve atrophy may be a common feature in α-mannosidosis. OCT technology helps detecting early outer retinal thinning which can progress with age and potentially leads to vision loss over time.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Humans; Infant; Male; Middle Aged; Nerve Degeneration; Optic Atrophy; Retina; Retinal Degeneration; Tomography, Optical Coherence; Young Adult; alpha-Mannosidosis
PubMed: 29859105
DOI: 10.1186/s13023-018-0829-z -
JIMD Reports Nov 2019Alpha-mannosidosis is a rare inherited metabolic disorder (OMIM #248500) caused by mutations in the enzyme α-mannosidase encoded by the gene . Patients have distinct...
Alpha-mannosidosis is a rare inherited metabolic disorder (OMIM #248500) caused by mutations in the enzyme α-mannosidase encoded by the gene . Patients have distinct physical and developmental features, but only limited information regarding standardized cognitive functioning of patients has been published. Here we contribute intellectual ability scores (IQ) on 12 patients with alpha-mannosidosis (ages 8-59 years, 10 males, 2 females). In addition, a pooled analysis was performed with data collected from this investigation and 31 cases obtained from the literature, allowing a comprehensive analysis of intellectual functioning in this rare disease. The initial and pooled analyses show that patients with alpha-mannosidosis have variable degrees of intellectual disability but show decline in IQ with age, particularly during the first decade of life. Patients treated with hematopoietic stem cell transplantation tend to show stabilized cognitive abilities.
PubMed: 31741826
DOI: 10.1002/jmd2.12073 -
Orphanet Journal of Rare Diseases Jun 2015Alpha-mannosidosis is caused by mutations in MAN2B1, leading to loss of lysosomal alpha-mannosidase activity. Symptoms include intellectual disabilities, hearing... (Clinical Trial)
Clinical Trial
BACKGROUND
Alpha-mannosidosis is caused by mutations in MAN2B1, leading to loss of lysosomal alpha-mannosidase activity. Symptoms include intellectual disabilities, hearing impairment, motor function disturbances, facial coarsening and musculoskeletal abnormalities.
METHODS
To study the genotype-phenotype relationship for alpha-mannosidosis 66 patients were included. Based on the predicted effect of the mutations and the subcellular localisation of mutant MAN2B1 in cultured cells, the patients were divided into three subgroups. Clinical and biochemical data were collected. Correlation analyses between each of the three subgroups of genotype/subcellular localisation and the clinical and biochemical data were done to investigate the potential relationship between genotype and phenotype in alpha-mannosidosis. Statistical analyses were performed using the SPSS software. Analyses of covariance were performed to describe the genotype-phenotype correlations. The phenotype parameters were modelled by the mutation group and age as a covariate. P values of <0.05 were considered as statistically significant.
RESULTS
Complete MAN2B1 genotypes were established for all patients. We found significantly higher scores in the Leiter-R test, lower concentrations of CSF-oligosaccharides, higher point scores in the Bruininks-Oseretsky Test of Motor Proficiency subtests (BOT-2); Upper limb coordination and Balance, and a higher FVC% in patients in subgroup 3, harbouring at least one variant that allows localisation of the mutant MAN2B1 protein to the lysosomes compared to subgrou 2 and/or subgroup 1 with no lysosomal localization of the mutant MAN2B1 protein.
CONCLUSION
Our results indicate a correlation between the MAN2B1 genotypes and the cognitive function, upper limb coordination, balance, FVC% and the storage of oligosaccharides in CSF. This correlation depends on the subcellular localisation of the mutant MAN2B1 protein.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Genetic Association Studies; Genotype; Humans; Male; Mannosidases; Oligosaccharides; Phenotype; Young Adult; alpha-Mannosidosis
PubMed: 26048034
DOI: 10.1186/s13023-015-0286-x -
Frontiers in Bioscience (Landmark... Feb 2023Alpha-mannosidosis is a rare lysosomal storage disorder, caused by decreased activity of α-D-mannosidase. This enzyme is involved in the hydrolysis of mannosidic...
BACKGROUND
Alpha-mannosidosis is a rare lysosomal storage disorder, caused by decreased activity of α-D-mannosidase. This enzyme is involved in the hydrolysis of mannosidic linkages in N-linked oligosaccharides. Due to the mannosidase defect, undigested mannose-rich oligosaccharides (Man2GlcNAc - Man9GlcNAc) accumulating in cells are excreted in large quantities in urine.
METHODS
In this work, we determined the levels of urinary mannose-rich oligosaccharides in a patient subjected to novel enzyme replacement therapy. Urinary oligosaccharides were extracted using solid phase extraction (SPE), labeled by fluorescent tag 2-aminobenzamide, and quantified by high-performance liquid chromatography (HPLC) with fluorescence detector (FLD). The identity of peaks was determined by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) mass spectrometry. In addition, the levels of urinary mannose-rich oligosaccharides were also quantified by 1H nuclear magnetic resonance (NMR) spectroscopy. The data were analyzed using one-tailed paired -test and Pearson's correlation tests.
RESULTS
Compared to levels before the administration of therapy, an approximately two-folds decrease in total mannose-rich oligosaccharides after one month of treatment was observed by NMR and HPLC. After four months, an approximately ten-folds significant decrease in total urinary mannose-rich oligosaccharides was detected, suggesting therapy effectiveness. A significant decrease in the levels of oligosaccharides with 7-9 mannose units was detected by HPLC.
CONCLUSIONS
The application of both HPLC-FLD and NMR in quantification of oligosaccharide biomarkers is a suitable approach for monitoring of therapy efficacy in alpha-mannosidosis patients.
Topics: Humans; Chromatography, High Pressure Liquid; alpha-Mannosidosis; Mannose; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy
PubMed: 36866557
DOI: 10.31083/j.fbl2802039 -
Frontiers in Genetics 2023Alpha-mannosidosis caused by mutations in the gene is a rare genetic disorder characterized by physical abnormalities and intellectual disabilities. The objective of...
Alpha-mannosidosis caused by mutations in the gene is a rare genetic disorder characterized by physical abnormalities and intellectual disabilities. The objective of this study was to analyze the carrier frequency and estimated incidence of alpha-mannosidosis in East Asian populations, as limited data exists on its incidence in this group. In this study, a total of 125,748 exomes from the gnomAD database was analyzed. Additionally, 5,305 data from the KOVA and 1,722 data from the KRGDB, both representing Korean populations, were included. The global carrier frequency of alpha-mannosidosis in gnomAD was 0.23%; the highest carrier frequency was observed in the Finnish at 0.49%, and East Asians had the second highest carrier frequency at 0.30%. Globally, the approximate incidence of alpha-mannosidosis was calculated at 1 in 784,535, l in 166,801 Europeans (Finnish), and l in 431,689 East Asians. By integrating the data from the 8,936 Koreans in gnomAD Korean, KOVA and KRGDB, the carrier frequency of alpha-mannosidosis in the Korean population was 0.04% and estimated incidence was 1 in 19,963,024. This study is the first to investigate the carrier frequencies of alpha-mannosidosis in East Asians and Koreans, including specific subpopulations, utilizing gnomAD and the Korean genomic database. The variant spectrum of genes in East Asians showed significant differences compared to other ethnic groups. Our data provide valuable reference information for future investigations into alpha-mannosidosis, aiding in understanding the genetic diversity and specific variants associated with the condition in East Asian populations.
PubMed: 38107468
DOI: 10.3389/fgene.2023.1297543