• Journal of mucopolysaccharidosis and rare diseases
• /
• 제3권1호
• /
• pp.14-19
• /
• 2017

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.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제3권1호
• /
• pp.20-27
• /
• 2017

Purpose: Mucopolysaccharidosis IV (MPS IV) is a disease characterized by deficient activity of N-acetylgalactosamine-6-sulfatase (GALNS) causing excessive lysosomal storage of keratan sulfate (KS). The identification of the relevant disaccharide units of KS after keratanase II digestion followed by liquid chromatography/tandem mass spectrometry detection (LC-MS/MS) is validated and applicable for the preliminary diagnosis of MPS IV. Methods: A total of 67 urine samples were collected and analyzed from 11 MPS IV patients comprising 10 MPS IVA and one MPS IVB patients, and 56 normal controls. Urinary glycosaminoglycan was first precipitated by the Alcian blue method followed by a digestion of keratanase II. The protonated species of the digested disaccharide products were detected by using multiple reaction monitoring experiment. Results: One particular disaccharide of KS was selected. The transition mass-to-charge (m/z) of the parent ion and its daughter ion after collision was $462.0{\rightarrow}97.0$, whereas the chondrosine used as an internal standard in this assay was m/z $353.9{\rightarrow}73.0$. The results corresponded well with the two-dimensional electrophoresis method. The quantities of urinary KS were significantly raised in confirmed MPS IV patients when comparing with those of normal controls ($170.2{\pm}81.1$ vs. $4.06{\pm}1.92{\mu}g/mL$). Conclusion: The LC-MS/MS method for MPS IVA determination is specific, sensitive, validated, and applicable for urinary KS quantification. This method can be used not only as a first-line biochemistry examination of MPS IVA, but also as an outcome survey after enzyme replacement therapy.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제1권1호
• /
• pp.2-4
• /
• 2015

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.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제5권1호
• /
• pp.17-21
• /
• 2021

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.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제3권1호
• /
• pp.9-13
• /
• 2017

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.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제1권2호
• /
• pp.49-53
• /
• 2015

Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder characterized by hypothalamic-pituitary dysfunction. Many features of PWS indicate a deficiency in growth hormone (GH) production, and these findings provide a rationale for GH therapy in PWS. It is possible that rhGH therapy could have beneficial effects in adults with PWS, similar to those in adults with GH deficiency (GHD) of non-syndromic cause. However, there is a paucity of data on the use of GH in adults with PWS. Here, the previous studies about efficacy and safety of rhGH therapy in PWS adults are summarized. Briefly, rhGH therapy in PWS adults may improve body composition, leading to increased lean body mass and decreased fat mass, as well as decreased subcutaneous and visceral adiposity without overall changes in body mass index. There may be at least transient deterioration in glucose homoeostasis in some PWS patients on rhGH therapy, which requires further study. In addition, clinical care guidelines for rhGH therapy in adults with PWS were suggested.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제1권2호
• /
• pp.40-43
• /
• 2015

Prader-Willi syndrome (PWS), a complex genetic disorder, arises from suppressed expression of paternally inherited imprinted genes on chromosome 15q11-q13. Characteristics include short stature, intellectual disability, behavioral problems, hypogonadism, obesity, and reduced bone and muscle. The life expectancy of persons with PWS has increased in recent years. Cardiovascular diseases, diabetes, dermatological, and orthopedic problems are common physical complaints in older people with PWS. Behavioral problems are major concerns in adults with PWS into old age. And aging is also associated with significant social and economic changes. Age-related physical morbidity, physical appearance, behavioral and psychiatric problems, functional decline and economic problems can be combined in older PWS. The care for older people with PWS requires a life span approach that recognizes the presence, progression, and consequences of specific morbidity.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제4권1호
• /
• pp.1-6
• /
• 2018

Lysosomal storage disorders are a group of rare inherited metabolic disorders with protean manifestations and variable severity ranging from attenuated forms to severe ones. It is necessary to diagnose and manage these disorders timely before irreversible damage occurs. Prior to the era of enzyme replacement therapy and newer therapeutics, only treatment option available was palliative care. Over the past two decades, extensive research in the lysosomal storage disorders has led to substantial expansion of our understanding about them. This mini review focusses on the spectrum, challenges faced in the diagnosis and therapy and remedial actions taken so far in lysosomal storage disorders in resource constrained country like India.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제4권1호
• /
• pp.11-13
• /
• 2018

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.

• Journal of mucopolysaccharidosis and rare diseases
• /
• 제1권1호
• /
• pp.19-22
• /
• 2015

In Growth Hormone (GH) therapy, suboptimal adherence is a common problem, reaching up to 82%, and there is a need for interventions to improve adherence and to maximize patients' growth potential eventually. Current studies have demonstrated the association between the rate of non-adherence and reduced height velocity. In order to maximize patients' potential to grow, an auto-injecting/recording device, such as $easypod^{TM}$, may help improve adherence and optimize the treatment effects of GH therapy. The use of $easypod^{TM}$ has contributed to high adherence rates: 87.5% and 93% in Bozzola et al.'s study and the $Easypod^{TM}$ Connect Observational study (ECOS), respectively. Improvement of adherence by $easypod^{TM}$ may lead to higher growth rates of patients receiving GH therapy. Additionally, patients' positive acceptability of $easypod^{TM}$ suggests $easypod^{TM}$ is a preferred device by patients for better adherence.