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Cureus Apr 2024Mongolian spots are bluish-grey, irregular, hyperpigmented macules present at birth or that appear in the first few weeks of life. They are classified as atypical if...
Mongolian spots are bluish-grey, irregular, hyperpigmented macules present at birth or that appear in the first few weeks of life. They are classified as atypical if they occur in unusual locations without spontaneous disappearance after infancy; or if new lesions continue to appear beyond early infancy. Although they are generally considered benign, recent studies have shown that atypical Mongolian spots may be associated with inborn errors of metabolism, such as lysosomal storage disorders and neurocristopathies. An 11-month-old male presented with multiple aberrant Mongolian spots on the abdomen, back, buttocks, arms, and legs, with the largest patch measuring 10x10 cm. Additionally, the child exhibited coarse facial features, a high-arched palate, low-set ears, and a depressed nasal bridge. Systemic examination revealed hepatosplenomegaly, fundus examination showed a hazy cornea, and the urine glycosaminoglycan test was positive, prompting us to conduct further research prioritising lysosomal storage disorders. The mucopolysaccharidosis (MPS) spot test was positive, and electrophoresis for MPS revealed bands for chondroitin sulfate and dermatan sulfate, confirming the diagnosis of MPS. Enzyme assay revealed no alpha-iduronidase activity and normal beta-galactosidase activity, thus confirming Hurler's disease. This case report highlights the importance of considering atypical Mongolian spots as a potential indicator of underlying storage disorders, enabling early intervention.
PubMed: 38765368
DOI: 10.7759/cureus.58501 -
Glycobiology Apr 2024Genetic deficiency of alpha-L-iduronidase causes mucopolysaccharidosis type I (MPS-I) disease, due to accumulation of glycosaminoglycans (GAGs) including...
Genetic deficiency of alpha-L-iduronidase causes mucopolysaccharidosis type I (MPS-I) disease, due to accumulation of glycosaminoglycans (GAGs) including chondroitin/dermatan sulfate (CS/DS) and heparan sulfate (HS) in cells. Currently, patients are treated by infusion of recombinant iduronidase or by hematopoietic stem cell transplantation. An alternative approach is to reduce the L-iduronidase substrate, through limiting the biosynthesis of iduronic acid. Our earlier study demonstrated that ebselen attenuated GAGs accumulation in MPS-I cells, through inhibiting iduronic acid producing enzymes. However, ebselen has multiple pharmacological effects, which prevents its application for MPS-I. Thus, we continued the study by looking for novel inhibitors of dermatan sulfate epimerase 1 (DS-epi1), the main responsible enzyme for production of iduronic acid in CS/DS chains. Based on virtual screening of chemicals towards chondroitinase AC, we constructed a library with 1,064 compounds that were tested for DS-epi1 inhibition. Seventeen compounds were identified to be able to inhibit 27%-86% of DS-epi1 activity at 10 μM. Two compounds were selected for further investigation based on the structure properties. The results show that both inhibitors had a comparable level in inhibition of DS-epi1while they had negligible effect on HS epimerase. The two inhibitors were able to reduce iduronic acid biosynthesis in CS/DS and GAG accumulation in WT and MPS-I fibroblasts. Docking of the inhibitors into DS-epi1 structure shows high affinity binding of both compounds to the active site. The collected data indicate that these hit compounds may be further elaborated to a potential lead drug used for attenuation of GAGs accumulation in MPS-I patients.
Topics: Mucopolysaccharidosis I; Humans; Fibroblasts; Glycosaminoglycans; Enzyme Inhibitors; Carbohydrate Epimerases; Molecular Docking Simulation; Antigens, Neoplasm; DNA-Binding Proteins; Neoplasm Proteins
PubMed: 38760939
DOI: 10.1093/glycob/cwae025 -
JAMA Network Open May 2024Newborn screening (NBS) for lysosomal storage disorders (LSDs) is becoming an increasing concern in public health. However, the birth prevalence of these disorders is...
IMPORTANCE
Newborn screening (NBS) for lysosomal storage disorders (LSDs) is becoming an increasing concern in public health. However, the birth prevalence of these disorders is rarely reported in the Chinese population, and subclinical forms of diseases among patients identified by NBS have not been evaluated.
OBJECTIVE
To evaluate the birth prevalence of the 6 LSDs in the Shanghai population and determine subclinical forms based on clinical, biochemical, and genetic characteristics.
DESIGN, SETTING, AND PARTICIPANTS
This cohort study included 50 108 newborns recruited from 41 hospitals in Shanghai between January and December 2021 who were screened for 6 LSDs using tandem mass spectrometry (MS/MS). Participants with screen-positive results underwent molecular and biochemical tests and clinical assessments. Data were analyzed from January 2021 through October 2022.
EXPOSURES
All participants were screened for Gaucher, acid sphingomyelinase deficiency (ASMD), Krabbe, mucopolysaccharidosis type I, Fabry, and Pompe diseases using dried blood spots.
MAIN OUTCOMES AND MEASURES
Primary outcomes were the birth prevalence and subclinical forms of the 6 LSDs in the Shanghai population. Disease biomarker measurements, genetic testing, and clinical analysis were used to assess clinical forms of LSDs screened.
RESULTS
Among 50 108 newborns (26 036 male [52.0%]; mean [SD] gestational age, 38.8 [1.6] weeks), the mean (SD) birth weight was 3257 (487) g. The MS/MS-based NBS identified 353 newborns who were positive. Of these, 27 newborns (7.7%) were diagnosed with 1 of 6 LSDs screened, including 2 newborns with Gaucher, 5 newborns with ASMD, 9 newborns with Krabbe, 8 newborns with Fabry, and 3 newborns with Pompe disease. The combined birth prevalence of LSDs in Shanghai was 1 diagnosis in 1856 live births, with Krabbe disease the most common (1 diagnosis/5568 live births), followed by Fabry disease (1 diagnosis/6264 live births), and ASMD (1 diagnosis/10 022 live births). Biochemical, molecular, and clinical analysis showed that early-onset clinical forms accounted for 3 newborns with positive results (11.1%), while later-onset forms represented nearly 90% of diagnoses (24 newborns [88.9%]).
CONCLUSIONS AND RELEVANCE
In this study, the combined birth prevalence of the 6 LSDs in Shanghai was remarkably high. MS/MS-based newborn screening, combined with biochemical and molecular genetic analysis, successfully identified and characterized newborns who were screen-positive, which may assist with parental counseling and management decisions.
Topics: Humans; Infant, Newborn; Neonatal Screening; China; Lysosomal Storage Diseases; Male; Female; Prevalence; Cohort Studies; Tandem Mass Spectrometry
PubMed: 38739391
DOI: 10.1001/jamanetworkopen.2024.10754 -
Cureus Apr 2024Sanfilippo syndrome is a childhood-onset (1-4 years) autosomal recessive lysosomal storage disease that presents as a neurodegenerative disease by targeting the brain... (Review)
Review
Sanfilippo syndrome is a childhood-onset (1-4 years) autosomal recessive lysosomal storage disease that presents as a neurodegenerative disease by targeting the brain and spinal cord. It is also known as mucopolysaccharidosis III. Mucopolysaccharidosis III is divided into four subtypes (A, B, C, or D). It can cause delayed speech, behavior problems, and features of autism spectrum disorder. Sanfilippo syndrome is of a higher prevalence within consanguineous families that carry its gene alteration. If both parents have a nonfunctional copy of a gene linked to this condition, their children will have a 25% (1 in 4) chance of developing the disease. In Saudi Arabia, the incidence rate is estimated at 2 per 100,000 live births. Recent research focused on promising treatment approaches, such as gene therapy, modified enzyme replacement therapy, and stem cells. These approaches work by exogenous administration of the proper version of the mutant enzyme (enzyme replacement therapy), cleaning the defective enzyme in individuals with glycolipid storage disorders (substrate reduction therapy), or using a pharmacological chaperone to target improperly folded proteins. However, there is currently no approved curative medication for Sanfilippo syndrome that can effectively halt or reverse the disorder.
PubMed: 38738088
DOI: 10.7759/cureus.58023 -
Orphanet Journal of Rare Diseases May 2024Mucopolysaccharidosis VII (MPS VII) is an ultra-rare, autosomal recessive, debilitating, progressive lysosomal storage disease caused by reduced activity of...
Disease characteristics, effectiveness, and safety of vestronidase alfa for the treatment of patients with mucopolysaccharidosis VII in a novel, longitudinal, multicenter disease monitoring program.
BACKGROUND
Mucopolysaccharidosis VII (MPS VII) is an ultra-rare, autosomal recessive, debilitating, progressive lysosomal storage disease caused by reduced activity of β-glucuronidase (GUS) enzyme. Vestronidase alfa (recombinant human GUS) intravenous enzyme replacement therapy is an approved treatment for patients with MPS VII.
METHODS
This disease monitoring program (DMP) is an ongoing, multicenter observational study collecting standardized real-world data from patients with MPS VII (N ≈ 50 planned) treated with vestronidase alfa or any other management approach. Data are monitored and recorded in compliance with Good Clinical Practice guidelines and planned interim analyses of captured data are performed annually. Here we summarize the safety and efficacy outcomes as of 17 November 2022.
RESULTS
As of the data cutoff date, 35 patients were enrolled: 28 in the Treated Group and seven in the Untreated Group. Mean (SD) age at MPS VII diagnosis was 4.5 (4.0) years (range, 0.0 to 12.4 years), and mean (SD) age at DMP enrollment was 13.9 (11.1) years (range, 1.5 to 50.2 years). Ten patients (29%) had a history of nonimmune hydrops fetalis. In the 23 patients who initiated treatment prior to DMP enrollment, substantial changes in mean excretion from initial baseline to DMP enrollment were observed for the three urinary glycosaminoglycans (uGAGs): dermatan sulfate (DS), -84%; chondroitin sulfate (CS), -55%; heparan sulfate (HS), -42%. Also in this group, mean reduction from initial baseline to months 6, 12, and 24 were maintained for uGAG DS (-84%, -87%, -89%, respectively), CS (-70%, -71%, -76%, respectively), and HS (+ 3%, -32%, and - 41%, respectively). All adverse events (AEs) were consistent with the known vestronidase alfa safety profile. No patients discontinued vestronidase alfa. One patient died.
CONCLUSIONS
To date, the DMP has collected invaluable MPS VII disease characteristic data. The benefit-risk profile of vestronidase alfa remains unchanged and favorable for its use in the treatment of pediatric and adult patients with MPS VII. Reductions in DS and CS uGAG demonstrate effectiveness of vestronidase alfa to Month 24. Enrollment is ongoing.
Topics: Humans; Mucopolysaccharidosis VII; Glucuronidase; Male; Child, Preschool; Female; Child; Enzyme Replacement Therapy; Recombinant Proteins; Infant; Longitudinal Studies; Adolescent
PubMed: 38715031
DOI: 10.1186/s13023-024-03176-z -
BioRxiv : the Preprint Server For... Apr 2024Enzymopathy disorders are the result of missing or defective enzymes. Amongst these enzymopathies, mucopolysaccharidosis type I, is a rare genetic lysosomal storage...
Enzymopathy disorders are the result of missing or defective enzymes. Amongst these enzymopathies, mucopolysaccharidosis type I, is a rare genetic lysosomal storage disorder caused by mutations in the gene encoding alpha-L-iduronidase (IDUA), ultimately causes toxic build-up of glycosaminoglycans (GAGs). There is currently no cure and standard treatments provide insufficient relief to the skeletal structure and central nervous system (CNS). Human memory T cells (Tm) migrate throughout the body's tissues and can persist for years, making them an attractive approach for cellular-based, systemic enzyme replacement therapy. Here, we tested genetically engineered, IDUA-expressing Tm as a cellular therapy in an immunodeficient mouse model of MPS I. Our results demonstrate that a single dose of engineered Tm leads to detectable IDUA enzyme levels in the blood for up to 22 weeks and reduced urinary GAG excretion. Furthermore, engineered Tm take up residence in nearly all tested tissues, producing IDUA and leading to metabolic correction of GAG levels in the heart, lung, liver, spleen, kidney, bone marrow, and the CNS. Our study indicates that genetically engineered Tm holds great promise as a platform for cellular-based enzyme replacement therapy for the treatment of mucopolysaccharidosis type I and potentially many other enzymopathies and protein deficiencies.
PubMed: 38712248
DOI: 10.1101/2024.04.23.590790 -
BioRxiv : the Preprint Server For... Apr 2024Mucopolysaccharidoses (MPS) are lysosomal storage diseases caused by defects in catabolism of glycosaminoglycans. MPS I, II, III and VII are associated with lysosomal...
Mucopolysaccharidoses (MPS) are lysosomal storage diseases caused by defects in catabolism of glycosaminoglycans. MPS I, II, III and VII are associated with lysosomal accumulation of heparan sulphate and manifest with neurological deterioration. Most of these neurological MPS currently lack effective treatments. Here, we report that, compared to controls, neuraminidase 1 (NEU1) activity is drastically reduced in brain tissues of neurological MPS patients and in mouse models of MPS I, II, IIIA, IIIB and IIIC, but not of other neurological lysosomal disorders not presenting with heparan sulphate storage. We further show that accumulated heparan sulphate disrupts the lysosomal multienzyme complex of NEU1 with cathepsin A (CTSA), β-galactosidase (GLB1) and glucosamine-6-sulfate sulfatase (GALNS) necessary to maintain enzyme activity, and that NEU1 deficiency is linked to partial deficiencies of GLB1 and GALNS in cortical tissues and iPSC-derived cortical neurons of neurological MPS patients. Increased sialylation of N-linked glycans in brain samples of human MPS III patients and MPS IIIC mice implicated insufficient processing of brain N-linked sialylated glycans, except for polysialic acid, which was reduced in the brains of MPS IIIC mice. Correction of NEU1 activity in MPS IIIC mice by lentiviral gene transfer ameliorated previously identified hallmarks of the disease, including memory impairment, behavioural traits, and reduced levels of the excitatory synapse markers VGLUT1 and PSD95. Overexpression of NEU1 also restored levels of VGLUT1-/PSD95-positive puncta in cortical neurons derived from iPSC of an MPS IIIA patient. Together, our data demonstrate that heparan sulphate-induced secondary NEU1 deficiency and aberrant sialylation of glycoproteins implicated in synaptogenesis, memory, and behaviour constitute a novel pathological pathway in neurological MPS spectrum crucially contributing to CNS pathology.
PubMed: 38712143
DOI: 10.1101/2024.04.26.587986 -
BioRxiv : the Preprint Server For... May 2024Since its first description in 1906 by Dr. Alois Alzheimer, Alzheimer's disease (AD) has been the most common type of dementia. Initially thought to be caused by...
A disease similarity approach identifies short-lived Niemann-Pick type C disease mice with accelerated brain aging as a novel mouse model for Alzheimer's disease and aging research.
Since its first description in 1906 by Dr. Alois Alzheimer, Alzheimer's disease (AD) has been the most common type of dementia. Initially thought to be caused by age-associated accumulation of plaques, in recent years, research has increasingly associated AD with lysosomal storage and metabolic disorders, and the explanation of its pathogenesis has shifted from amyloid and tau accumulation to oxidative stress and impaired lipid and glucose metabolism aggravated by hypoxic conditions. However, the underlying mechanisms linking those cellular processes and conditions to disease progression have yet to be defined. Here, we applied a disease similarity approach to identify unknown molecular targets of AD by using transcriptomic data from congenital diseases known to increase AD risk, namely Down Syndrome, Niemann Pick Disease Type C (NPC), and Mucopolysaccharidoses I. We uncovered common pathways, hub genes, and miRNAs across and models of these diseases as potential molecular targets for neuroprotection and amelioration of AD pathology, many of which have never been associated with AD. We then investigated common molecular alterations in brain samples from an NPC disease mouse model by juxtaposing them with brain samples of both human and mouse models of AD. Detailed phenotypic and molecular analyses revealed that the NPC mouse model can serve as a potential short-lived model for AD research and for understanding molecular factors affecting brain aging. This research represents the first comprehensive approach to congenital disease association with neurodegeneration and a new perspective on AD research while highlighting shortcomings and lack of correlation in diverse models. Considering the lack of an AD mouse model that recapitulates the physiological hallmarks of brain aging, the characterization of a short-lived NPC mouse model will further accelerate the research in these fields and offer a unique model for understanding the molecular mechanisms of AD from a perspective of accelerated brain aging.
PubMed: 38712089
DOI: 10.1101/2024.04.19.590328 -
BioRxiv : the Preprint Server For... Jun 2024Phenylketonuria (PKU), hereditary tyrosinemia type 1 (HT1), and mucopolysaccharidosis type 1 (MPSI) are autosomal recessive disorders linked to the phenylalanine...
Phenylketonuria (PKU), hereditary tyrosinemia type 1 (HT1), and mucopolysaccharidosis type 1 (MPSI) are autosomal recessive disorders linked to the phenylalanine hydroxylase () gene, fumarylacetoacetate hydrolase () gene, and alpha-L-iduronidase () gene, respectively. Potential therapeutic strategies to ameliorate disease include corrective editing of pathogenic variants in the and genes and, as a variant-agnostic approach, inactivation of the 4-hydroxyphenylpyruvate dioxygenase () gene, a modifier of HT1, via adenine base editing. Here we evaluated the off-target editing profiles of therapeutic lead guide RNAs (gRNAs) that, when combined with adenine base editors correct the recurrent P281L variant, R408W variant, or W402X variant or disrupt the gene in human hepatocytes. To mitigate off-target mutagenesis, we systematically screened hybrid gRNAs with DNA nucleotide substitutions. Comprehensive and variant-aware specificity profiling of these hybrid gRNAs reveal dramatically reduced off-target editing and reduced bystander editing. Lastly, in a humanized P281L mouse model, we showed that when formulated in lipid nanoparticles (LNPs) with adenine base editor mRNA, selected hybrid gRNAs revert the PKU phenotype, substantially enhance on-target editing, and reduce bystander editing . These studies highlight the utility of hybrid gRNAs to improve the safety and efficacy of base-editing therapies.
PubMed: 38712058
DOI: 10.1101/2024.04.22.590531 -
American Journal of Medical Genetics.... May 2024Molecular genetics enables more precise diagnoses of skeletal dysplasia and other skeletal disorders (SDs). We investigated the clinical utility of multigene panel...
Clinical utility of comprehensive gene panel testing for common and rare causes of skeletal dysplasia and other skeletal disorders: Results from the largest cohort to date.
Molecular genetics enables more precise diagnoses of skeletal dysplasia and other skeletal disorders (SDs). We investigated the clinical utility of multigene panel testing for 5011 unrelated individuals with SD in the United States (December 2019-April 2022). Median (range) age was 8 (0-90) years, 70.5% had short stature and/or disproportionate growth, 27.4% had a positive molecular diagnosis (MDx), and 30 individuals received two MDx. Genes most commonly contributing to MDx were FGFR3 (16.9%), ALPL (13.0%), and COL1A1 (10.3%). Most of the 112 genes associated with ≥1 MDx were primarily involved in signal transduction (n = 35), metabolism (n = 23), or extracellular matrix organization (n = 17). There were implications associated with specific care/treatment options for 84.4% (1158/1372) of MDx-positive individuals; >50% were linked to conditions with targeted therapy approved or in clinical development, including osteogenesis imperfecta, achondroplasia, hypophosphatasia, and mucopolysaccharidosis. Forty individuals with initially inconclusive results became MDx-positive following family testing. Follow-up mucopolysaccharidosis enzyme activity testing was positive in 14 individuals (10 of these were not MDx-positive). Our findings showed that inclusion of metabolic genes associated with SD increased the clinical utility of a gene panel and confirmed that integrated use of comprehensive gene panel testing with orthogonal testing reduced the burden of inconclusive results.
PubMed: 38702915
DOI: 10.1002/ajmg.a.63646