Collaboration through the Asia Pacific MPS Network (APMN), Asia Pacific MPS Registry (APMR), and Association for Research of MPS & Rare Diseases (ARMRD)

Cho, Sung Yoon Association for Research of MPS and Rare Diseases 2015 Journal of mucopolysaccharidosis and rare disease Vol.1 No.1

Though the rate of incidence of each rare disease, including mucopolysaccharidosis (MPS), is low, this is not the case if they are taken as a whole. Rare diseases often have genetic causes and vary in type. However, the signs and symptoms vary greatly by disease, making it difficult to make accurate diagnoses and conduct necessary research, which is why we believe it is a field that deserves more attention and research. It is important to establish an infrastructure of experts in each country and promote cooperation within the Asia-Pacific region in order to improve specialist training and communication. Given the need for a system of cooperation, the Asia Pacific MPS Network (APMN) was established by several MPS experts in South Korea, Japan, and Taiwan in January 2013. Thereafter, the Asia Pacific MPS Registry (APMR), an electronic remote data system, was established by the APMN. Then, the Association for Research of MPS & Rare Diseases (ARMRD), an academic society that supports research on MPS and other rare diseases, was established by President Dong-Kyu Jin in April in 2015. The main task of the ARMRD is to support APMN-related work. The ARMRD published a uniform guideline that reflects the characteristics and circumstances of local patients through the Korean MPS Expert Council. Now, the APMN, APMR, and the annual Korean MPS Symposium are supported by ARMRD. Organizations like the APMN and APMR are necessary because international cooperation and collaboration are needed to conduct clinical trials on those diseases. ARMRD members hope to encourage the interest of experts and researchers of MPS & rare diseases as well as active participation in the research and treatment of patients suffering from rare diseases, including MPS, to ultimately improve the quality of life of the patients as well as their families.

Enzyme Replacement Therapy for Lysosomal Storage Disease in Indonesia

Sjarif, Damayanti Rusli,Hafifah, Cut Nurul Association for Research of MPS and Rare Diseases 2018 Journal of mucopolysaccharidosis and rare disease Vol.4 No.1

Rare diseases are life threatening or chronically debilitating diseases with a low prevalence (less than 2,000 people in a population), which includes lysosomal storage diseases. These diseases are often seen as unimportant especially in developing countries, such as Indonesia, due to small number of patients. National Rare Disease Center in Indonesia was pioneered almost 20 years ago and officially established in 2017 by the Indonesian Minister of Health. Lysosomal storage disease become the most commonly found inborn errors of metabolism (IEM) in Indonesia due to easily accessible diagnostic facilities. Currently there are 7 patients receiving ERT in this mixed-donation scheme, one patient with Gaucher disease and 6 patients with MPS type II. Few challenges for ERT in Indonesia include importation through special access scheme, preparation of ERT infusion in intensive care settting, and cost of treatment. Even with limited resources, healthcare professionals in Indonesia have been giving the best care possible for rare disease patients, especially to provide diagnostic facilities through collaboration and treatment options for treatable rare diseases. Improvements in care for rare disease patients are still needed.

Newborn Screening for Lysosomal Storage Diseases in Taiwan

Lin, Hsiang-Yu,Chuang, Chih-Kuang,Lin, Shuan-Pei Association for Research of MPS and Rare Diseases 2017 Journal of mucopolysaccharidosis and rare disease Vol.3 No.1

Lysosomal storage diseases (LSDs) are a group of rare inherited metabolic disorders caused by the deficiency of specific lysosomal enzymes and subsequent accumulation of substrates. Enzyme deficiency leads to progressive intra-lysosomal accumulation of the incompletely degraded substances, which cause dysfunction and destruction of the cell and eventually multiple organ damage. Patients have a broad spectrum of clinical phenotypes which are generally not specific for some LSDs, leading to missed or delayed diagnosis. Due to the availability of treatment including enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation for some LSDs, early diagnosis is important. ERT products have been approved with optimal outcomes for some LSDs in the recent decades, including Gaucher, Fabry, mucopolysaccharidosis (MPS) I, Pompe, MPS VI, MPS II, and MPS IVA diseases. ERT can stabilize the clinical condition, prevent disease progression, and improve the long-term outcome of these diseases, especially if started prior to irreversible organ damage. Based on the availability of therapy and suitable screening methods in the recent years, some LSDs, including Pompe, Fabry, Gaucher, MPS I, MPS II, and MPS VI diseases have been incorporated into nationwide newborn screening panels in Taiwan.

Phenotypic Characterization of MPS IIIA (Sgshmps^3a/ Sgshmps^3a) Mouse Model

Park, Sung Won,Ko, Ara,Jin, Dong-kyu Association for Research of MPS and Rare Diseases 2018 Journal of mucopolysaccharidosis and rare disease Vol.4 No.1

Mucopolysaccharidosis IIIA is a heritable neurodegenerative disorder resulting from the dysfunction of the lysosomal hydrolase sulphamidase. This leads to the primary accumulation of the complex carbohydrate heparan sulphate in a wide range of tissues and CNS degeneration. Characterization of animal model is the beginning point of the therapeutic clinical trial. Mouse model has a limitation in that it is not a human and does not have all of the disease phenotypes. Therefore, delineate of the phenotypic characteristics of MPS IIIA mouse model prerequisite for the enzyme replace treatment for the diseases. We designed 6-month duration of phenotypic characterization of MPS IIIA mouse biochemically, behaviorally and histologically. We compared height and weight of MPS IIIA mouse with wild type from 4 weeks to 6 months in both male and female. At 6 months, we measured GAG storage in urine kidney, heart, liver, lung and spleen. The brain GAG storage is presented with Alcian blue staining, immunohistochemistry, and electron-microscopy. The neurologic phenotype is evaluated by brain MRI and behavioral study including open field test, fear conditioning, T-maze test and Y-maze test. Especially behavioral tests were done serially at 4month and 6month. This study will show the result of the MPS IIIA mouse model phenotypic characterization. The MPS IIIA mouse provides an excellent model for evaluating pathogenic mechanisms of disease and for testing treatment strategies, including enzyme or cell replacement and gene therapy.

Novel Therapeutic Approaches to Mucopolysaccharidosis Type III

Yang, Aram Association for Research of MPS and Rare Diseases 2021 Journal of mucopolysaccharidosis and rare disease Vol.5 No.1

Mucopolysaccharidosis type III (MPS III) or Sanfilippo disease is an orphan-inherited lysosomal storage disease. It is one of the most common MPS subtypes. The classical presentation is an infantile-onset neurodegenerative disease characterized by intellectual regression, behavioral and sleep disturbances, loss of ambulation, and early death. Unlike other MPS, no disease-modifying therapy has been approved. Here, we review the curative therapy developed for MPS III, from historically ineffective hematopoietic stem cell transplantation and substrate reduction therapy to the promising enzyme replacement therapy or adeno-associated/lentiviral vector-mediated gene therapy. Preclinical studies are presented with recent translational first-in-man trials. We also present experimental research with preclinical mRNA and gene-editing strategies. Lessons from animal studies and clinical trials have highlighted the importance of early therapy before extensive neuronal loss. Disease-modifying therapy for MPS III will likely mandate the development of new early diagnosis strategies.

Joint Problems in Patients with Mucopolysaccharidosis Type II

Kim, Min-Sun,Kim, Jiyeon,Noh, Eu Seon,Kim, Chiwoo,Cho, Sung Yoon,Jin, Dong-Kyu Association for Research of MPS and Rare Diseases 2021 Journal of mucopolysaccharidosis and rare disease Vol.5 No.1

Hunter syndrome or mucopolysaccharidosis type II (MPS-II) (OMIM 309900) is a rare lysosomal storage disorder caused by deficiency in the activity of the enzyme iduronate-2-sulfatase. This enzyme is responsible for the catabolism of the following two different glycosaminoglycans (GAGs): dermatan sulfate and heparan sulfate. The lysosomal accumulation of these GAG molecules results in cell, tissue, and organ dysfunction. Patients can be broadly classified as having one of the following two forms of MPS II: a severe form and an attenuated form. In the severe form of the disease, signs and symptoms (including neurological impairment) develop in early childhood, whereas in the attenuated form, signs and symptoms develop in adolescence or early adulthood, and patients do not experience significant cognitive impairment. The involvement of the skeletal-muscle system is because of essential accumulated GAGs in joints and connective tissue. MPS II has many clinical features and includes two recognized clinical entities (mild and severe) that represent two ends of a wide spectrum of clinical severities. However, enzyme replacement therapy is likely to have only a limited impact on bone and joint disease based on the results of MPS II studies. The aim of this study was to review the involvement of joints in MPS II.

A Review of Gaucher Disease in Korea

Sohn, Young Bae Association for Research of MPS and Rare Diseases 2021 Journal of mucopolysaccharidosis and rare disease Vol.5 No.1

Gaucher disease (GD, OMIM #230800 OMIM#230800) is a rare, autosomal recessive inherited metabolic disorder caused by mutation in GBA1 encoding the lysosomal enzyme, glucocerebrosidase. The deficiency of glucocerebrosidase leads to an accumulation of its substrate, glucosylceramide in macrophages of various tissues. Common clinical manifestations include cytopenia, splenomegaly, hepatomegaly, and bone lesions. The phenotype of GD is classified into three clinical categories: Type 1 (non-neuronopathic) is characterized by involvements on the viscera, whereas types 2 and 3 (neuronopathic) are associated with not only visceral symptoms but also neurological impairment, either severe in type 2 or variable in type 3. A diagnosis of GD can be confirmed by demonstrating the deficiency of acid glucocerebrosidase activity in leukocytes. Mutations in the GBA1 should be identified as they may be of prognostic value in some cases. Biomarkers including Chitotriosidase, CCL18, and glucosylsphingosine (lyso-GL1) are useful in diagnosis and treatment monitoring. Currently available disease-specific treatment in Korea consists of intravenous enzyme replacement therapy and substrate reduction therapy. For enhancing long-term prognosis, the onset of Parkinson's disease and Lewy body dementia, or the occurrence of a blood disease or cancer (hepatocellular carcinoma) should be monitored in older patients. The development of new strategies that can modify the neurological phenotype are expected, especially in Asia including Korea, where the prevalence of neuronopathic GD is relatively higher than that in western countries.

Diagnosis and Management of Patients with Mucopolysaccharidoses in Malaysia

Ngu, Lock-Hock Association for Research of MPS and Rare Diseases 2018 Journal of mucopolysaccharidosis and rare disease Vol.4 No.1

In Malaysia, diagnosis and treatment of patients with mucopolysaccharidoses (MPS) is mainly localized at Hospital Kuala Lumpur, which is the national referral center for rare diseases. To date there are 83 patients diagnosed with MPS in our center, with MPS II being the commonest. The Malaysian National Medicines Policy second edition has a specific section on the orphan drugs which includes recombinant human enzyme for enzyme replacement therapy (ERT) in MPS. So far, National Pharmaceutical Regulatory Agency Malaysia has approved recombinant human enzyme for MPS types I (Loranidase), II (idursulfase), IVA (elosulfase alfa), and VI (Galsufase). Access to Idursulfase beta (another recombinant human enzyme for MPS II) and vestronidase alfa-vjbk (MPS VII) required special authorization on named patient basic. Currently there are 25 patients receiving ERT, 70% of the funding are from Ministry of Health (MOH), the remaining 30% are from various charitable funds and humanitarian programs. Thirteen newly diagnosed patients have to queue for an additional fund. Four patients have been treated with Hematopoietic stem cell transplant. MOH has also published guidelines regarding the patient selection criteria for ERT and treatment monitoring schedule.

Newborn Screening of Lysosomal Storage Diseases, Including Mucopolysaccharidoses

Kim, Su Jin Association for Research of MPS and Rare Diseases 2017 Journal of mucopolysaccharidosis and rare disease Vol.3 No.1

Tandem mass spectrometry and other new technologies for the multiplex and quantitative analysis of dried blood spots have emerged as powerful techniques for the early screening and assessment of newborns for lysosomal storage diseases (LSDs). Screening newborns for these diseases is important, since treatment options, including enzyme replacement therapy or hematopoietic transplantation, are available for some LSDs, such as infant-onset Pompe disease, Fabry disease, some types of mucopolysaccharidoses (MPSs), and Krabbe disease. For these diseases, early initiation of treatment, before symptoms worsen, often leads to better clinical outcomes. Several problems, however, are associated with newborn screening for LSDs, including the development of accurate test methods to reduce low false-positive rates and treatment guidelines for late-onset or mild disease variants, the high costs associated with multiplex assays, and ethical issues. In this review, we discuss the history, current status, and ethical problems associated with the newborn screening for LSDs, including MPSs.

Clinical Problems in ML II and III: Extra-skeletal Manifestations

Park, Sung Won Association for Research of MPS and Rare Diseases 2016 Journal of mucopolysaccharidosis and rare disease Vol.2 No.1

Mucolipidoses II and III alpha/beta (ML II and ML III) are lysosomal disorders in which the essential mannose-6-phosphate recognition marker is not synthesized onto lysosomal hydrolases and other glycoproteins. The disorders are caused by mutations in GNPTAB, which encodes two of three subunits of the heterohexameric enzyme, N-acetylglucosamine-1-phosphotransferase ML II, recognizable at birth, often causes intrauterine growth impairment and sometimes the prenatal "Pacman" dysplasia. The main postnatal manifestations of ML II include gradual coarsening of neonatally evident craniofacial features, early cessation of statural growth and neuromotor development, dysostosis multiplex and major morbidity by hardening of soft connective tissue about the joints and in the cardiac valves. Fatal outcome occurs often before or in early childhood. ML III with clinical onset rarely detectable before three years of age, progresses slowly with gradual coarsening of the facial features, growth deficiency, dysostosis multiplex, restriction of movement in all joints before or from adolescence, painful gait impairment by prominent hip disease. Cognitive handicap remains minor or absent even in the adult, often wheelchair-bound patient with variable though significantly reduced life expectancy. As yet, there is no cure for individuals affected by these diseases. So, clinical manifestations and conservative treatment is important. This review aimed to highlight the extra-skeletal clinical problems in ML II and III.