• Journal of mucopolysaccharidosis and rare diseases
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• 제5권1호
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• pp.17-21
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• 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 Microbiology and Biotechnology
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• 제31권1호
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• pp.163-170
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• 2021

Enzyme replacement therapy for lysosomal storage diseases usually requires recombinant enzymes containing mannose-6-phosphate (M6P) glycans for cellular uptake and lysosomal targeting. For the first time, a strategy is established here for the in vitro mannosyl-phosphorylation of high-mannose type N-glycans that utilizes a recombinant Mnn14 protein derived from Saccharomyces cerevisiae. Among a series of N-terminal- or C-terminal-deleted recombinant Mnn14 proteins expressed in Pichia pastoris, rMnn1477-935 with deletion of N-terminal 76 amino acids spanning the transmembrane domain (46 amino acids) and part of the stem region (30 amino acids), showed the highest level of mannosyl-phosphorylation activity. The optimum reaction conditions for rMnn1477-935 were determined through enzyme assays with a high-mannose type N-glycan (Man8GlcNAc2) as a substrate. In addition, rMnn1477-935 was shown to mannosyl-phosphorylate high-mannose type N-glycans (Man7-9GlcNAc2) on recombinant human lysosomal alpha-glucosidase (rhGAA) with remarkably high efficiency. Moreover, the majority of the resulting mannosyl-phosphorylated glycans were bis-form which can be converted to bis-phosphorylated M6P glycans having a superior lysosomal targeting capability. An in vitro N-glycan mannosyl-phosphorylation reaction using rMnn1477-935 will provide a flexible and straightforward method to increase the M6P glycan content for the generation of "Biobetter" therapeutic enzymes.

• Journal of Interdisciplinary Genomics
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• 제2권2호
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• pp.20-25
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• 2020

Mucopolysaccharidosis type III (MPS III or Sanfilippo syndrome) is a multisystem lysosomal storage disease that is inherited in an autosomal recessive manner. It consists of four subtypes (MPS IIIA, B, C, and D), each characterized by the deficiency of different enzymes that catalyze the metabolism of the glycosaminoglycan heparan sulfate at the lysosomal level. The typical clinical manifestation of MPS III includes progressive central nervous system (CNS) degeneration with accompanying systemic manifestations. Disease onset is typically before the age of ten years and death usually occurs in the second or third decade due to neurological regression or respiratory tract infections. However, there is currently no treatment for CNS symptoms in patients with MPS III. Invasive and non-invasive techniques that allow drugs to pass through the blood brain barrier and reach the CNS are being tested and have proven effective. In addition, the application of genistein treatment as a substrate reduction therapy is in progress.

• Clinical and Experimental Pediatrics
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• 제46권6호
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• pp.615-619
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• 2003

시스틴증은 상염색체 열성으로 발생하는 매우 드문 용해소체 축적병으로서, 용해소체 막을 통한 시스틴 운반의 장애로 발생한다. 용해소체 내 시스틴의 축적과 결정화에 의해 전신의 여러 조직에 파괴가 진행되어 성장 장애, Fanconi 증후군, 신부전, 눈의 이상, 내분비 질환 등이 나타난다. 치료제인 cysteamine의 투여가 예후를 향상시킬 수 있으므로 조기 진단과 치료가 중요하다. 저자들은 성장 장애를 주소로 내원한 12세 남아에서 slit-lamp 검사와 혈액 백혈구 시스틴 농도 측정을 통하여 시스틴증을 확진하고 cysteamine 치료를 시행하면서 추적 관찰 중이다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제20권4호
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• pp.263-267
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• 2017

Patients with lysosomal acid lipase (LAL) deficiency and glycogen storage disease (GSD) demonstrated hepatomegaly and dyslipidemia. In our case, a 6-year-old boy presented with hepatosplenomegaly. At 3 years of age, GSD had been diagnosed by liver biopsy at another hospital. He showed elevated serum liver enzymes and dyslipidemia. Liver biopsy revealed diffuse microvesicular fatty changes in hepatocytes, septal fibrosis and foamy macrophages. Ultrastructural examination demonstrated numerous lysosomes that contained lipid material and intracytoplasmic cholesterol clefts. A dried blood spot test revealed markedly decreased activity of LAL. LIPA gene sequencing identified the presence of a novel homozygous mutation (p.Thr177Ile). The patient's elevated liver enzymes and dyslipidemia improved with enzyme replacement therapy. This is the first report of a Korean child with LAL deficiency, and our findings suggest that this condition should be considered in the differential diagnosis of children with hepatosplenomegaly and dyslipidemia.

• Journal of mucopolysaccharidosis and rare diseases
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• 제4권1호
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• pp.21-25
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• 2018

Fabry disease is a hereditary lysosomal storage disorder caused by the reduction or absence of lysosomal enzyme alpha-galactosidase A and the accumulation of glycosphingolipids, such as globotriaosylceramide (Gb3), in various organs, including the heart. The prevention of cardiac involvement in Fabry disease can only be achieved by enzyme replacement therapy (ERT), and the method of assessing the efficacy of ERT should be confirmed. Changes in the electrocardiogram, such as the shortening of PQ interval, prolongation of QTc and repolarization abnormalities as well as left ventricular hypertrophy in voltage criteria, can be used to identify Fabry disease patients; however, the usefulness of electrocardiograms for evaluating the efficacy of ERT is limited. The assessment of left ventricular hypertrophy using echocardiography has been established to evaluate the efficacy of ERT during long-term period. A new technique involving speckled tracking method might be useful for detecting early cardiac dysfunction and identifying the effect of ERT for a relatively short period. The estimation of left ventricular hypertrophy using cardiac magnetic resonance (CMR) is also useful for assessing the efficacy of ERT. Identifying late gadolinium enhancement in CMR may affect the effectiveness of ERT, and the new technique of T1 mapping might be useful for monitoring the accumulation of Gb3 during ERT. Histopathology in cardiac biopsy specimens is another potentially useful method for identifying the accumulation of GB3; however, the use of histopathology to evaluate of the efficacy of ERT is limited because of the invasive nature of an endomyocardial biopsy.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권1호
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• pp.1-6
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• 2021

Next-generation sequencing (NGS) technologies have changed the process of genetic diagnosis from a gene-by-gene approach to syndrome-based diagnostic gene panel sequencing (DPS), diagnostic exome sequencing (DES), and diagnostic genome sequencing (DGS). A priori information on the causative genes that might underlie a genetic condition is a prerequisite for genetic diagnosis before conducting clinical NGS tests. Theoretically, DPS, DES, and DGS do not require any information on specific candidate genes. Therefore, clinical NGS tests sometimes detect disease-related pathogenic variants in genes underlying different conditions from the initial diagnosis. These clinical NGS tests are expensive, but they can be a cost-effective approach for the rapid diagnosis of rare disorders with genetic heterogeneity, such as the glycogen storage disease, familial intrahepatic cholestasis, lysosomal storage disease, and primary immunodeficiency. In addition, DES or DGS may find novel genes that that were previously not linked to human diseases.

• 대한유전성대사질환학회지
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• 제6권1호
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• pp.32-39
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• 2006

저자들은 출생 후 정상적인 발달을 보이다가 생후 6개월부터 의식과 운동 발달의 퇴행을 보이던 13개월 환아에서 효소 검사를 시행하여 ${\beta}$-galactosidase의 결핍을 확인하고 $GM_1$-gangliosidosis type 1으로 진단하였지만, 후에 추가적으로 시행한 효소 검사에서 ${\alpha}$-neuraminidase의 결핍도 발견되어 galactosialidosis로 진단한 증례를 경험하였기에 문헌 고찰과 함께 보고하고자 한다.

• 대한유전성대사질환학회지
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• 제4권1호
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• pp.23-29
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• 2004

시스틴증은 상염색체 열성으로 발생하는 매우 드문 용해소체 축적병으로서, 용해소체 막을 통한 시스틴 운반의 장애로 발생한다. 용해소체 내 시스틴의 축척과 결정화에 의해 전신의 여러 조직에 파괴가 진행되어 성장 장애, Fanconi 증후군, 신부전, 눈의 이상, 내분비 질환 등이 나타난다. 치료제인 cysteamine의 투여가 예후를 향상시킬 수 있으므로 조기 진단과 치료가 중요하다. 저자들은 성장 장애를 주소로 내원한 12세 남아에서 slit-lamp 검사와 혈액 백혈구 시스틴 농도 측정을 통하여 시스틴증을 확진하고 cysteamine 치료를 시행하면서 추적 관찰 중이다.

• Journal of Genetic Medicine
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• 제15권1호
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• pp.28-33
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• 2018

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by the deficiency of ${\alpha}$-galactosidase A. Patients with classical FD present acroparesthesia, hypohidrosis, cornea verticillata, disseminated angiokeratoma, and microalbuminuria in childhood, and develop life-threatening renal, cardiac, and cerebrovascular complications typically after the fourth decade of life. To date, more than 700 mutations responsible for FD have been identified in the human GLA gene. Herein, we report a novel GLA mutation, c.1117_1141del25 (p.Gly373Profs*10), identified in an 11-year-old Korean boy with FD presenting early cardiac and neurologic manifestation and in other affected family members. The boy had acroparesthesia, hypohidrosis, cornea verticillata, and left ventricular hypertrophy. His mother and sister also had acroparesthesia. Two males on the mother's side had similar pain and died of unknown causes. The plasma ${\alpha}$-galactosidase A activity (4.1 nmol/hr/mg protein) of the patient was markedly lower than the mean value of the controls. The plasma level of globotriaosylsphingosine was elevated in the patient and all the carriers. We concluded the novel GLA mutation c.1117_1141del25 is a pathogenic mutation for FD, probably related to the early cardiac manifestation of FD.