• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.2
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• pp.87-92
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• 2015

Mucopolysaccharidosis (MPS) is an inherited disease entity associated with lysosomal enzyme deficiencies. MPS type 2, also known as Hunter syndrome, has a characteristic morphology primarily involving x-l inked recessive defects and iduronate-2-sulfatase gene mutation. The purpose of this case report is to provide important clues to help pediatricians identify Hunter syndrome patients earlier (i.e., before the disease progresses). A 30-month-old boy showed developmental delay and decreased speech ability. Physical examinations revealed a flat nose and extensive Mongolian spots. Brain magnetic resonance images (MRIs) showed bilateral multiple patchy T2 hyperintense lesions in the periventricular and deep white matter, several cyst-like lesions in the body of the corpus callosum, and diffuse brain atrophy, which were in keeping with the diagnosis. Based on these findings, the patient was suspected of having MPS. In the laboratory findings, although the genetic analysis of IDS (Iduronate-2-sulfatase) did not show any pathogenic variant, the enzymatic activity of IDS was not detected. We could confirm the diagnosis of MPS, because other sulfatases, such as ${\alpha}$-L-iduronidase, were detected in the normal range. Early enzymatic replacement therapy is essential and has a relatively good prognosis. Therefore, early diagnosis should be made before organ damage becomes irreversible, and brain MRIs can provide additional diagnostic clues to help distinguish the disorder.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.3
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• pp.101-109
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• 2015

Classic galactosemia (OMIM #230400) is an autosomal recessive inherited metaboic disorder caused by a deficiency of the galactose-1-phosphate uridyltransferase (GALT, EC2.7.7.12) due to mutations in the GALT gene. If untreated, classic galactosemia is a potentially lethal disease presenting with poor feeding, vomiting, jaundice, liver failure, increased bleeding tendency, and septicemia leading to death within a few days after birth. Since 2006, expansion of newborn screening has been enabled the early diagnosis and early intervention of classic galactosemia in Korea. However, newborn screening, followup testing for confirmatory diagnosis and intervention for galactosemia continue to present challenges. In Korea, the prevalence of the classic galactosemia is considered relatively low compared to that of western countries. And the genotype is also clearly different from those of other population. Therefore, our own guideline for confirmatory diagnosis and intervention is needed. Here, the diagnostic algorithm for galactosemia after positive newborn screening result in Korea has been proposed. Considering the low prevalence and different mutation spectrum in Koreans, the early mutation analysis of GALT gene could be a useful tool for the accurate diagnosis and making any treatment decision.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.1
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• pp.30-34
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• 2018

Niemann Pick type C disease (NPC) is an inherited progressive neurodegenerative disorder, due to defects of intracellular lipid trafficking and storage. Hepatosplenomegaly may prevail, while progressive neurodegenerative symptoms such as cerebellar involvement, dystonia, vertical supranuclear ophthalmoplegia, cataplexy, and eventually seizures starting at juvenile or late infantile period may accompany after normal early development. Here we describe a 3-year-old Korean boy with NPC who presented with splenomegaly at age 3. Liver biopsy showed characteristic foamy cell stained by periodic acid-schiff, and molecular analysis for NPC1 identified the compound heterozygous mutations, novel mutation of c.1631G>A (p.Trp544Ter) and c.2662C>T (p. Pro888Ser) as a known mutation. Filipin was strongly stained with unesterified cellular cholesterol in the patient's skin fibroblasts. The patient has received migulstat since age 3 years and his long-term outcome is needed to be observed.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.5 no.1
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• pp.1-8
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• 2005

Glutaric acidemia (GA) type II is a very rare inherited disorder that have no accruate figure on its icidende. People with Glutaric acidemia type II have an enzyme that does not work properly. Two specific enzymes are associated with Glutaric acidemia type II:1. Electron transfer flavoprotein (ETF), 2. ETF-ubiquinone oxidoreductase (ETF-QO). Both of these enzymes have similar functions in the body, and children with Glutaric acidemia type II may lack one or the other of these enzymes. They play an important role in breaking down fats and proteins, and help the body to produce energy. GA II clinically manifested as (1) neonatal onset with congenital anomalies (2) neonatal onset without anomalies, and (3) mild and/or later onset. The first two groups are sometimes said to have multiple acyl CoA dehydrogenation deficiency-severe and the third to have multiple acyl CoA dehydrogenation deficiency-mild. The course and age at presentation of later-onset glutaric acidemia type II is extremely variable, therefore it is difficult to diagnosis. We experienced one case of late onset form glutaric acidemia type II with afebrile status epilepticus-like convulsion.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.24 no.1
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• pp.1-9
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• 2024

Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episode (MELAS) is a rare maternally inherited disorder primarily caused by mutations in mitochondrial DNA, notably the m.3243A>G mutation in the MT-TL1 gene. This mutation impairs mitochondrial function crucial for cellular energy production, particularly in high-energy-demanding organs such as the brain and muscles. MELAS manifests as recurrent stroke-like episodes, seizures, diabetes mellitus, cardiomyopathy, and other multisystemic symptoms that are often present in childhood. The diagnosis combines genetic testing, clinical evaluation, and neuroimaging, with elevated lactate levels and characteristic magnetic resonance imaging (MRI) findings as key indicators. Treatment focuses on symptomatic management and enhancement of mitochondrial function through L-arginine, coenzyme Q10, high-dose vitamins, and taurine supplementation. Studies have identified additional genetic variants linked to MELAS, including mutations in POLG and other mitochondrial genes, further complicating the genetic landscape. Emerging therapies, particularly gene therapy and mitochondria-targeting drugs, offer promising avenues for addressing the underlying genetic defects and improving mitochondrial functioning. Furthermore, ongoing studies continue to enhance our understanding and management of MELAS, with the aim of reducing its burden and improving patient outcomes and quality of life. This review summarizes the current knowledge on the genetics, clinical features, diagnosis, and treatment of MELAS, highlighting the latest advancements and future directions for therapeutic interventions.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.20 no.1
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• pp.24-28
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• 2020

Type III Glycogen storage disease (Type III GSD, OMIM#232400) is a genetic metabolic disorder in which undigested glycogen accumulates in the organs due to lack of glycogen debranching enzyme caused by AGL mutation. The clinical symptoms of type III GSD include hepatomegaly, delayed growth, hypoglycemia and muscle weakness. These clinical symptoms are similar to those of other types of GSD, making it difficult to distinguish clinically. The authors report a case of type III GSD diagnosed by gene panel sequencing. A 11-month old male patient was presented with hepatomegaly. In liver biopsy, glycogen was accumulated in hepatocytes, suggesting GSDs. For differential diagnosis of types of GSD, gene panel sequencing for GSDs was performed. As a result, two novel pathogenic compound heterozygous variants: c.311_312del (p.His104Argfs*15) and c.3314+1G>A in AGL were detected and the patient was diagnosed as type III GSD. After diagnosis, he started dietary treatment with cornstarch, and has been free from complications. After two years, two same variants were also identified in the chorionic villous sampling of the pregnant mother, and the fetus was diagnosed as type III GSD. Gene panel sequencing is useful for diagnosis of disease which is indistinguishable by clinically and has high genetic heterogeneity, such as GSD. After diagnosis, familial genetic analysis can provide adequate genetic counseling and rapid diagnosis.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.23 no.2
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• pp.39-44
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• 2023

Hereditary tyrosinemia type 1 (HT-1) is a metabolic disorder caused by biallelic pathogenic variants in the fumarylacetoacetate hydrolase (FAH) gene, which impairs the function of the FAH enzyme, resulting in the accumulation of tyrosine's toxic metabolites in hepatocytes and renal tubular cells. As a consequence, individuals with HT-1 exhibit symptomatic manifestations. Rapid diagnosis and treatment of HT-1 can prevent short-term death and long-term complications. A 15-day-old boy presented to the outpatient department with elevated levels of tyrosine on his newborn screening tests conducted at the age of 3 and 10 days, respectively. Further blood tests revealed increased levels of alpha-fetoprotein and amino acids including tyrosine and threonine. Urine organic acid tests indicated a significant elevation in tyrosine metabolites, as well as the presence of succinylacetone (SA), which led to the diagnosis of HT-1. Two pathogenic and likely pathogenic variants of FAH compatible with HT-1 were also detected. He began a tyrosine-restricted diet at one month old and received nitisinone (NTBC) at two months old. With continued treatment, the patient's initially elevated AFP level, detection of SA in the urine, and mild hepatomegaly showed improvement. During four years and seven months of treatment, there were no exceptional complications apart from an increase in tyrosine levels and a delay in speech. We report a case of tyrosinemia type 1 detected through newborn screening, treated with dietary restriction and NTBC, with a good prognosis.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.3
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• pp.99-106
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• 2018

Mucolipidosis type III (pseudo-Hurler polydystrophy) is a mucolipids degrading disorder caused by a mutation in the GNPTAB gene and is inherited by autosomal recessive. It is diagnosed by examining highly concentrated mucolipids in blood and the diagnosis can be confirmed by genetic testing. Mucolipidosis type III is a rare and progressive metabolic disorder. Its initial signs and symptoms usually occur around 3 years of age. Clinical manifestations of the disease include slow growth, joint stiffness, arthralgia, skeletal abnormalities, heart valve abnormalities, recurrent respiratory infection, distinctive facial features, and mild intellectual disability. Here, we are presenting two siblings of mucolipidosis type III, a 4-year-old female and a 2 years and 7 months old male with features of delayed growth and coarse face. The diagnosis was confirmed by [c.2715+1G>A(p.Glu906Leufs*4), c.2544del(p.Glu849Lysfs*22)] mutation in targeted gene panel sequencing. In this case, c.2544del is a heterozygote newly identified mutation in mucolipidosis type III and was not found in the control group including the genome aggregation database. And it is interpreted as a pathogenic variant considering the association with phenotype. Here, we report a Korean mucolipidosis type III patients with novel mutations in GNPTAB gene who have been treated since early childhood. Owing to recent development of molecular genetic techniques, it was possible to make early diagnosis and treatment with pamidronate was initiated appropriately in case 1. In addition to these supportive therapies, efforts must be made to develop fundamental treatment for patients with early diagnosis of mucolipidosis.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.21 no.1
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• pp.15-21
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• 2021

Purpose: Urea cycle disorder (UCD) is an inherited inborn error of metabolism, acting on each step of urea cycle that cause various phenotypes. The purpose of the study was to investigate the long-term clinical consequences in different groups of UCD to characterize it. Methods: Twenty-two patients with UCD genetically confirmed were enrolled at Pusan National University Children's hospital and reviewed clinical features, biochemical and genetic features retrospectively. Results: UCD diagnosed in the present study included ornithine transcarbamylase deficiency (OTCD) (n=10, 45.5%), argininosuccinate synthase 1 deficiency (ASSD) (n=6, 27.3%), carbamoyl-phosphate synthetase 1 deficiency (CPS1D) (n=3, 13.6%), hyperornithinemia-hyperammonemia-homocitrullinuria syndrome (HHHS) (n=2, 9.1%), and arginase-1 deficiency (ARG1D) (n=1, 4.5%). The age at the diagnosis was 32.7±66.2 months old (range 0.1 to 228.0 months). Eight (36.4%) patients with UCD displayed short stature. Neurologic sequelae were observed in eleven (50%) patients with UCD. Molecular analysis identified 37 different mutation types (14 missense, 6 nonsense, 6 deletion, 6 splicing, 3 delins, 1 insertion, and 1 duplication) including 14 novel variants. Progressive growth impairment and poor neurological outcomes were associated with plasma isoleucine and leucine concentrations, respectively. Conclusion: Although combinations of treatments such as nutritional restriction of proteins and use of alternative pathways for discarding excessive nitrogen are extensively employed, the prognosis of UCD remains unsatisfactory. Prospective clinical trials are necessary to evaluate whether supplementation with BCAAs might improve growth or neurological outcomes and decrease metabolic crisis episodes in patients with UCD.

• Clinical and Experimental Pediatrics
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• v.59 no.sup1
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• pp.103-106
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• 2016

Bartter syndrome (BS) is an inherited renal tubular disorder characterized by low or normal blood pressure, hypokalemic metabolic alkalosis, and hyperreninemic hyperaldosteronism. Type III BS is caused by loss-of-function mutations in CLCNKB encoding basolateral ClC-Kb. The clinical phenotype of patients with CLCNKB mutations has been known to be highly variable, and cases that are difficult to categorize as type III BS or other hereditary tubulopathies, such as Gitelman syndrome, have been rarely reported. We report a case of a 10-year-old Korean boy with atypical clinical findings caused by a novel CLCNKB mutation. The boy showed intermittent muscle cramps with laboratory findings of hypokalemia, severe hypomagnesemia, and nephrocalcinosis. These findings were not fully compatible with those observed in cases of BS or Gitelman syndrome. The CLCNKB mutation analysis revealed a heterozygous c.139G>A transition in exon 13 [p.Gly(GGG)465Glu(GAG)]. This change is not a known mutation; however, the clinical findings and in silico prediction results indicated that it is the underlying cause of his presentation.