scholarly journals Modeling Mucopolysaccharidosis Type II in the Fruit Fly by Using the RNA Interference Approach

Life ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 263
Author(s):  
Laura Rigon ◽  
Nicole Kucharowski ◽  
Franka Eckardt ◽  
Reinhard Bauer

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disorder that occurs due to the deficit of the lysosomal enzyme iduronate 2-sulfatase (IDS) that leads to the storage of the glycosaminoglycan heparan- and dermatan-sulfate in all organs and tissues. It is characterized by important clinical features and the severe form presents with a heavy neurological involvement. However, almost nothing is known about the neuropathogenesis of MPS II. To address this issue, we developed a ubiquitous, neuronal, and glial-specific knockdown model in Drosophila melanogaster by using the RNA interference (RNAi) approach. Knockdown of the Ids/CG12014 gene resulted in a significant reduction of the Ids gene expression and enzymatic activity. However, glycosaminoglycan storage, survival, molecular markers (Atg8a, Lamp1, Rab11), and locomotion behavior were not affected. Even strongly reduced, IDS-activity was enough to prevent a pathological phenotype in a MPS II RNAi fruit fly. Thus, a Drosophila MPS II model requires complete abolishment of the enzymatic activity.

2020 ◽  
Vol 6 (3) ◽  
pp. 73 ◽  
Author(s):  
Barbara K. Burton ◽  
Rachel Hickey ◽  
Lauren Hitchins

Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is a rare, progressive multisystemic lysosomal storage disorder with significant morbidity and premature mortality. Infants with MPS II develop signs and symptoms of the disorder in the early years of life, yet diagnostic delays are very common. Enzyme replacement therapy is an effective treatment option. It has been shown to prolong survival and improve or stabilize many somatic manifestations of the disorder. Our initial experience with newborn screening in 162,000 infants was previously reported. Here, we update that experience with the findings in 339,269 infants. Measurement of iduronate-2-sulfatase (I2S) activity was performed on dried blood spot samples submitted for other newborn screening disorders. A positive screen was defined as I2S activity less than or equal to 10% of the daily median. In this series, 28 infants had a positive screening test result, and four other infants had a borderline result. Three positive diagnoses of MPS II were established, and 25 were diagnosed as having I2S pseudodeficiency. The natural history and the clinical features of MPS II make it an ideal target for newborn screening. Newborn screening was effective in identifying affected infants in our population with an acceptable rate of false positive results.


Diagnostics ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 854
Author(s):  
Cheng-Yung Lin ◽  
Hsiang-Yu Lin ◽  
Chih-Kuang Chuang ◽  
Po-Hsiang Zhang ◽  
Ru-Yi Tu ◽  
...  

Mucopolysaccharidosis type II (MPS II) is an X-linked disorder resulting from a deficiency in iduronate 2-sulfatase (IDS), which is reported to be caused by gene mutations in the iduronate 2-sulfatase (IDS) gene. Many IDS mutation sites have not yet had their causal relationship with MPS II characterized. We employed a gain-of-function strategy whereby we microinjected different mutated zebrafish ids (z-ids) mRNAs corresponded to human IDS gene into zebrafish embryos, and then measured their total IDS enzymatic activity and observed the occurrence of defective phenotypes during embryonic development. We examined three known mutation sites for human IDS genes (h-IDS) associated with MPS II symptoms, including h-IDS-P86L, -S333L and -R468W, which corresponded to z-ids-P80L, -S327L and -R454W. When these three mutated z-ids mRNAs were overexpressed in zebrafish embryos, the IDS enzymatic activity of the total proteins extracted from the injected embryos was not increased compared with the endogenous IDS of the untreated embryos, which suggests that the IDS enzymatic activity of these three mutated z-ids was totally lost, as expected. Additionally, we observed defective phenotypes in these injected embryos, resulting from the failed IDS enzyme breakdown, which, in turn, has a dominant negative effect on the endogenous wild-type IDS function. These phenotypes were similar to the clinical symptoms observed in MPS II pathogenesis. We further studied six uncharacterized IDS mutation sites as identified by the Taiwanese MPS newborn screening programs. We propose a novel IDS enzyme activity assay combined with phenotypic observation in zebrafish embryos, as an alternative platform for quickly providing a valuable index for preliminarily assessment of any identified IDS point mutation gene that has not yet been characterized, in the context of its role in MPS II development.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Marie Julianne C. Racoma ◽  
Maria Kristina Karizza B. Calibag ◽  
Cynthia P. Cordero ◽  
Mary Ann R. Abacan ◽  
Mary Anne D. Chiong

Abstract Background Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is an X-linked multisystem disorder characterized by glycosaminoglycan (GAG) accumulation, caused by a deficiency of iduronate-2-sulfatase (I2S). Enzyme replacement therapy (ERT) with recombinant idursulfase (IDS), the standard of care, was started in the Philippines in 2017. This study reviewed the clinical outcomes in idursulfase-treated and untreated Filipino MPS II patients who were included in the local Lysosomal Storage Disease (LSD) registry of the Institute of Human Genetics-National Institutes of Health (IHG-NIH) from January 1999 to December 2019. Methods A retrospective audit of records of MPS II patients listed in the registry was done. Qualified patients were divided into two cohorts: idursulfase-treated group (patients on enzyme replacement therapy, ERT, for ≥ 6 months) and untreated group. Baseline characteristics, including demographic data, biochemical results, neurocognitive classification, respiratory involvement, mortality, and adverse events, were recorded. Height, weight, cardiac pathology, liver and spleen sizes, six-minute walking test (6MWT), joint mobility, were determined at baseline and at year 1 and 2 of follow up. Results Forty male patients were included in this review, with only 8 receiving ERT since 2017. The mean age at diagnosis was 6.99 years (SD 4.15; 0.75–20) and mean age at start of ERT was 14.03 years (SD 7.1; 4–21.5), more delayed than previous reports. Eighty percent have early progressive phenotype which was higher than reported average. The early growth pattern differed in our Filipino cohort, but was followed by the expected slowed growth in later years. Improvements in the following endpoints were observed in the treated cohort: height and weight, cardiac disease, liver and spleen sizes, and joint mobility. There were also positive effects on respiratory involvement and mortality rate. Adverse events were consistent with previous reports. Conclusions ERT is generally well tolerated and effective in reducing GAG storage and improving clinical endpoints among our Filipino MPS II patients. In untreated patients, typical disease progression was observed.


2020 ◽  
Author(s):  
Marie Julianne Castillo Racoma ◽  
Maria Kristina Karizza B. Calibag ◽  
Mary Anne D. Chiong ◽  
Mary Ann R. Abacan ◽  
Cynthia Cordero

Abstract Background: Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is an X-linked multisystem disorder characterized by glycosaminoglycan (GAG) accumulation, caused by a deficiency of iduronate-2-sulfatase (I2S). Enzyme replacement therapy (ERT) with recombinant I2S, the standard of care, was started in the Philippines in 2017. This study reviewed the clinical outcomes in idursulfase-treated and untreated Filipino MPS II patients who were included in the local Lysosomal Storage Disease (LSD) registry of the Institute of Human Genetics-National Institutes of Health (IHG-NIH) from January 1999 to December 2019.Methods: A retrospective audit of records of MPS II patients listed in the registry was done. Qualified patients were divided into two cohorts: idursulfase-treated group (patients on enzyme replacement therapy, ERT, for >6 months) and untreated group. Baseline characteristics, including demographic data, biochemical results, neurocognitive classification, respiratory involvement, mortality, and adverse events, were recorded. Height, weight, cardiac pathology, liver and spleen sizes, six-minute walk test (6MWT), joint mobility, were determined at baseline and at year 1 and 2 of follow up.Results: Forty male patients were included in this review, with 8 receiving ERT since 2017. The mean age at diagnosis was 6.99 years (SD 4.15; 0.75-20) and mean age at start of ERT was 14.03 years (SD 7.1; 4-21.5), more delayed than previous reports. Eighty percent have early progressive phenotype which was higher than reported average. The early growth pattern differed in our Filipino cohort, but was followed by the expected slowed growth in later years. Improvements in the following endpoints were observed in the treated cohort: height and weight, cardiac disease, liver and spleen sizes, and joint mobility. There were also positive effects on respiratory involvement and mortality rate. Adverse events were consistent with previous reports.Conclusions: ERT is generally well tolerated and effective in reducing GAG storage and improving clinical endpoints among our Filipino MPS II patients. In untreated patients, typical disease progression was observed.


2020 ◽  
Vol 19 (5) ◽  
pp. 364-370
Author(s):  
Tatiana K. Kruchina ◽  
Konstantin V. Bruchikov ◽  
Gennady A. Novik

Background. Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is a rare hereditary lysosomal storage disease associated with iduronate-2-sulfatase deficiency. Patients with MPS II require life-long enzyme replacement therapy (ERT) to replace the deficiency of endogenous enzyme. There are two medications — idursulfase and idursulfase beta — that are licensed and recommended for these patients in Russian Federation. However, it is well known that ERT can cause hypersensitivity reactions development.Clinical Case Description. The ERT (idursulfase in the dose of 0.5 mg/kg once per week) onset in the male patient with severe MPS II was at the age of 2.5 years. Hypersensitivity reactions (urticaria, fever) were noted incidentally, thus, the premedication with antihistamines and antipyretics was performed. The ERT side effects has aggravated at the age of 8 years despite the glucocorticosteroids admission and infusion rate reduction up to 8–16 ml/h. That is why we have changed the medication on idursulfase beta with major clinical response: we have achieved control on both disease itself and hypersensitivity reactions.Conclusion. The availability of two ERT medications for patients with MPS II expands treatment opportunities. In case of any allergic reactions due to idursulfase, the change on idursulfase beta reduces the risk of any ERT complications with sufficient control of MPS II course.


2021 ◽  
Vol 132 ◽  
pp. S147
Author(s):  
Kruti Patel ◽  
Laura Smith ◽  
Tania Seabrook ◽  
Alec Tzianabos ◽  
Lindsay Schulman ◽  
...  

Author(s):  
Miguel Sampayo-Cordero ◽  
Bernat Miguel-Huguet ◽  
Andrea Malfettone ◽  
José Manuel Pérez-García ◽  
Antonio Llombart-Cussac ◽  
...  

Background: Case reports are usually excluded from systematic reviews. Patients with rare diseases are more dependent on novel individualized strategies than patients with common diseases. We reviewed and summarized the novelties reported by case reports in mucopolysaccharidosis type II (MPS-II) patients treated with enzyme replacement therapy (ERT). Methods: We selected the case reports included in a previous meta-analysis of patients with MPS-II treated with ERT. Later clinical studies evaluating the same topic of those case reports were reported. Our primary aim was to summarize novelties reported in previous case reports. Secondary objectives analyzed the number of novelties evaluated in subsequent clinical studies and the time elapsed between the publication of the case report to the publication of the clinical study. Results: We identified 11 innovative proposals in case reports that had not been previously considered in clinical studies. Only two (18.2%) were analyzed in subsequent nonrandomized cohort studies. The other nine novelties (81.8%) were analyzed in later case reports (five) or were not included in ulterior studies (four) after more than five years from their first publication. Conclusions: Case reports should be included in systematic reviews of rare disease to obtain a comprehensive summary of the state of research and offer valuable information for healthcare practitioners.


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