• Clinical and Experimental Pediatrics
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• 제59권sup1호
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• pp.37-40
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• 2016

Mucopolysaccharidosis type III (MPS III) is a rare genetic disorder caused by lysosomal storage of heparan sulfate. MPS IIIB results from a deficiency in the enzyme alpha-N-acetyl-D-glucosaminidase (NAGLU). Affected patients begin showing behavioral changes, progressive profound mental retardation, and severe disability from the age of 2 to 6 years. We report a patient with MPS IIIB with a long-term follow-up duration. He showed normal development until 3 years. Subsequently, he presented behavioral changes, sleep disturbance, and progressive motor dysfunction. He had been hospitalized owing to recurrent pneumonia and epilepsy with severe cognitive dysfunction. The patient had compound heterozygous c.1444C>T (p.R482W) and c.1675G>T (p.D559Y) variants of NAGLU. Considering that individuals with MPS IIIB have less prominent facial features and skeletal changes, evaluation of long-term clinical course is important for diagnosis. Although no effective therapies for MPS IIIB have been developed yet, early and accurate diagnosis can provide important information for family planning in families at risk of the disorder.

• Journal of mucopolysaccharidosis and rare diseases
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• 제2권1호
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• pp.5-7
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• 2016

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.

• Journal of mucopolysaccharidosis and rare diseases
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• 제3권1호
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• pp.1-8
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• 2017

Mucopolysaccharidosis (MPS) type III, or Sanfilippo syndrome is a rare autosomal recessive lysosomal storage disorder. It is caused by a deficiency of one of four enzymes involved in the degradation of the glycosaminoglycan (GAG) heparan sulfate. The resultant cellular accumulation of heparan sulfate causes various clinical manifestations. MPS III is divided into four subtypes depending on the deficient enzyme: MPS IIIA, MPS IIIB, MPS IIIC and MPS IIID. All the subtypes show similar clinical features and are characterized by progressive degeneration of the central nervous system (CNS). Main purpose of the treatment for MPS III is to prevent neurologic deterioration. However, conventional enzyme replacement therapy has a limitation due to inability to cross the blood-brain barrier. Several experimental treatment options for MPS III are being developed.

• 대한유전성대사질환학회지
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• 제12권1호
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• pp.5-13
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• 2012

I 세포 질환(뮤코지방증 2형; MIM 252500)과 pseudo-Hurler polydystrophy (뮤코지방증 3형; MIM 252600)는 세포내 비정상적인 리소좀 관련 운송으로 인해 발병한다. 특징적인 소견으로는 섬유아 세포의 세포질에 다수의 봉입체, 뮤코다당뇨의 부재, 혈청 내 리소좀 효소 활성도의 증가, GlcNAc-phosphotransferase 활성도의 감소를 보인다. 이 연구에서는 GlcNAc-phosphotransferase 알파/베타 아형에 대한 knockout 마우스의 표현형과 생화학적 특징을 조사하였다. 또한, 태반으로부터 추출한 리소좀 농축 분획을 knockout 마우스에 투여하였을 때 체중 증가에 대한 효과를 볼 수 있는지에 대해 알아보고자 하였다. knockout 마우스는 뮤코지방증 2형 환자에서 그렇듯이 정상적인 체중 증가를 보이지 않았고 낮은 골밀도를 보였다. 게다가 knockout 마우스의 피부 섬유 아세포의 배양액에서는 리소좀 효소 활성도가 증가한 반면, 세포 내에서는 리소좀 효소 활성도가 감소되어 있는 것을 확인할 수 있었으며 이러한 특징은 뮤코지방증 2형 환자에서 볼 수 있는 특징과 일치한다. knockout 마우스의 꼬리 정맥내로 태반에서 추출한 리소좀 농축 분획을 투여한 결과, 체중이 증가하는 것을 확인할 수 있었고, 반면 생리식염수를 투여한 knockout 마우스의 경우는 체중이 증가하지 않았다. 결론적으로, knockout 마우스의 표현형과 생화학적 특징이 뮤코지방증 2형 환자와 유사하다는 것을 확인하였으며, 리소좀 농축 분획의 치료적 가능성을 증명하였다. 더 큰 범위의 동물 실험을 진행할 필요가 있으나, 이 연구는 질병에 대한 동물 모델을 개발하고 리조솜 농축 분획의 치료적 가능성을 제시하는 것을 통해 현재까지 치료가 불가능한 뮤코지방증 2형의 새로운 치료 방법의 가능성을 열었다고 볼 수 있다.

• Parasites, Hosts and Diseases
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• 제56권5호
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• pp.409-418
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• 2018

Acanthamoeba spp. are free-living protozoa that are opportunistic pathogens for humans. Cysteine proteases of Acanthamoeba have been partially characterized, but their biochemical and functional properties are not clearly understood yet. In this study, we isolated a gene encoding cysteine protease of A. castellanii (AcCP) and its biochemical and functional properties were analyzed. Sequence analysis of AcCP suggests that this enzyme is a typical cathepsin L family cysteine protease, which shares similar structural characteristics with other cathepsin L-like enzymes. The recombinant AcCP showed enzymatic activity in acidic conditions with an optimum at pH 4.0. The recombinant enzyme effectively hydrolyzed human proteins including hemoglobin, albumin, immunoglobuins A and G, and fibronectin at acidic pH. AcCP mainly localized in lysosomal compartment and its expression was observed in both trophozoites and cysts. AcCP was also identified in cultured medium of A. castellanii. Considering to lysosomal localization, secretion or release by trophozoites and continuous expression in trophozoites and cysts, the enzyme could be a multifunctional enzyme that plays important biological functions for nutrition, development and pathogenicity of A. castellanii. These results also imply that AcCP can be a promising target for development of chemotherapeutic drug for Acanthamoeba infections.

• Journal of mucopolysaccharidosis and rare diseases
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• 제3권2호
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• pp.37-40
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• 2017

Mucopolysaccharidosis (MPS) is caused by accumulation of the glycosaminoglycans in all tissues due to decreased activity of the lysosomal enzyme. Patients exhibit multisystemic signs and symptoms in a chronic and progressive manner, especially with changes in the skeleton, cardiopulmonary system, central nervous system, cornea, skin, liver, and spleen. In the past, treatment of MPS was limited to enzyme replacement therapy (ERT). The outcome for affected patients improved with the introduction of new technologies as hematopoietic stem cell transplantation, relegated to specific situations after ERT became available. Intrathecal ERT may be considered in situations of high neurosurgical risk but still it is experimental in humans. New insights on the pathophysiology of MPS disorders are leading to alternative therapeutic approaches, as gene therapy, inflammatory response modulators and substrate reduction therapy. In this paper, we will highlight the recent novel treatment and clinical trials for MPS and discuss with the goal of fostering an understanding of this field.

• Journal of mucopolysaccharidosis and rare diseases
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• 제5권1호
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• pp.1-7
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• 2021

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.

• Journal of Genetic Medicine
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• 제20권1호
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• pp.6-14
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• 2023

Fabry disease (FD), a rare X-linked lysosomal storage disorder, is caused by mutations in the α-galactosidase A gene gene encoding α-galactosidase A (α-Gal A). The functional deficiency of α-Gal A results in progressive accumulation of neutral glycosphingolipids, causing multi-organ damages including cardiac, renal, cerebrovascular systems. The current treatment is comprised of enzyme replacement therapy (ERT), oral pharmacological chaperone therapy and adjunctive supportive therapy. ERT has been introduced 20 years ago, changing the outcome of FD patients with proven effectiveness. However, FD patients have many unmet needs. ERT needs a life-long intravenous therapy, inefficient bio-distribution, and generation of anti-drug antibodies. Migalastat, a pharmacological chaperone, augmenting α-Gal A enzyme activity only in patients with mutations amenable to the therapy, is now available for clinical practice. Furthermore, these therapies should be initiated before the organ damage becomes irreversible. Development of novel drugs aim at improving the clinical effectiveness and convenience of therapy. Clinical trial of next generation ERT is underway. Polyethylene glycolylated enzyme has a longer half-life and potentially reduced antigenicity, compared with standard preparations with longer dosing interval. Moss-derived enzyme has a higher affinity for mannose receptors, and seems to have more efficient access to podocytes of kidney which is relatively resistant to reach by conventional ERT. Substrate reduction therapy is currently under clinical trial. Gene therapy has now been started in several clinical trials using in vivo and ex vivo technologies. Early results are emerging. Other strategic approaches at preclinical research level are stem cell-based therapy with genome editing and systemic mRNA therapy.

• Clinical and Experimental Pediatrics
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• 제55권3호
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• pp.88-92
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• 2012

Purpose: Mucopolysaccharidosis type II (MPS II or Hunter syndrome) is a rare lysosomal storage disorder caused by iduronate-2-sulfatase (IDS) deficiency. MPS II causes a wide phenotypic spectrum of symptoms ranging from mild to severe. IDS activity, which is measured in leukocyte pellets or fibroblasts, was reported to be related to clinical phenotype by Sukegawa-Hayasaka et al. Measurement of residual plasma IDS activity using a fluorometric assay is simpler than conventional measurements using skin fibroblasts or peripheral blood mononuclear cells. This is the first study to describe the relationship between plasma IDS activity and clinical phenotype of MPS II. Methods: We hypothesized that residual plasma IDS activity is related to clinical phenotype. We classified 43 Hunter syndrome patients as having attenuated or severe disease types based on clinical characteristics, especially intellectual and cognitive status. There were 27 patients with the severe type and 16 with the attenuated type. Plasma IDS activity was measured by a fluorometric enzyme assay using 4-methylumbelliferyl- ${\alpha}$-iduronate 2-sulphate. Results: Plasma IDS activity in patients with the severe type was significantly lower than that in patients with the attenuated type ($p$=0.006). The optimal cut-off value of plasma IDS activity for distinguishing the severe type from the attenuated type was 0.63 $nmol{\cdot}4hr^{-1}{\cdot}mL^{-1}$. This value had 88.2% sensitivity, 65.4% specificity, and an area under receiver-operator characteristics (ROC) curve of 0.768 (ROC curve analysis; $p$=0.003). Conclusion: These results show that the mild phenotype may be related to residual lysosomal enzyme activity.

• The Korean Journal of Pain
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• 제23권3호
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• pp.207-210
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• 2010

Fabry disease is an X-linked lysosomal disease caused by deficiency of ${\alpha}$-galactosidase, in which early diagnosis may be missed due to the wide variety of clinical symptoms presenting during disease progression. A 13 year-old boy visited our pain clinic complaining of pricking and burning pain in the toe tips of both feet. Continuous epidural infusion for pain management was performed because of oral analgesics ineffectiveness. The patient underwent ${\alpha}$-galactosidase A (GLA) enzyme analysis based on the clinical impression of Fabry disease from pain with a peripheral neuropathic component and history of anhidrosis. He was diagnosed with Fabry disease after confirming mutation of the GLA gene through a screening test of GLA activity. Enzyme replacement therapy was initiated and pain was tolerated with oral analgesics.