• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.2
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• pp.43-49
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• 2018

Maple syrup urine disease (MSUD, OMIM#248600) is a rare and autosomal recessively-inherited metabolic disorder that is caused by mutations in the branched-chain ${\alpha}$-ketoacid dehydrogenase (BCKDH) genes. It prevents the normal breakdown of branched-chain amino acids (BCAAs), such as leucine, isoleucine, and valine, and leads to poor feeding, lethargy, abnormal movements, seizure, and death if untreated. Here, we report the case of a Korean newborn of biochemically- and genetically-confirmed MSUD manifesting lethargy and central apnea, the acute state of which was successfully treated. The molecular genetic investigation revealed two novel heterozygous mutations (p.Ala32Phefs*48 and p.Val 130Phe) in BCKDHB, and both parents were confirmed as carriers. We emphasize the importance of early diagnosis and prompt introduction of specific treatment for MSUD in life saving and prognosis.

• Clinical and Experimental Pediatrics
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• v.54 no.1
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• pp.36-39
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• 2011

Bartter syndrome (BS) is a clinically and genetically heterogeneous inherited renal tubular disorder characterized by renal salt wasting, hypokalemic metabolic alkalosis and normotensive hyperreninemic hyperaldosteronism. There have been several case reports of BS complicated by focal segmental glomerulosclerosis (FSGS). Here, we have reported the case of a BS patient who developed FSGS and subsequent end-stage renal disease (ESRD) and provided a brief literature review. The patient presented with classic BS at 3 months of age and developed proteinuria at 7 years. Renal biopsy performed at 11 years of age revealed a FSGS perihilar variant. Hemodialysis was initiated at 11 years of age, and kidney transplantation was performed at 16 years of age. The post-transplantation course has been uneventful for more than 3 years with complete disappearance of BS without the recurrence of FSGS. Genetic study revealed a homozygous p.Trp(TGG)610Stop(TGA) mutation in the CLCNKB gene. In summary, BS may be complicated by secondary FSGS due to the adaptive response to chronic salt-losing nephropathy, and FSGS may progress to ESRD in some patients. Renal transplantation in patients with BS and ESRD results in complete remission of BS.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.555-561
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• 1998

Hypophosphatasia is a rare metabolic disorder which manifests characteristics such as abnormal mineralization of bone and dental tissues, diminished serum and tissue alkaline phosphatase, and increased urinary secretion of PEA. It inherited as an autosomal recessive or dominant trait and occurs in all races. In general, hypophosphatasia can be classified in 4 subtypes which are the perinatal, infantile, childhood, adult type depending upon the age at presentation and severity. In young children with Hypophosphatasia the long bones show irregular defects, and the skull showes poor calcification. In older children with premature closure of the skull sutures there may be multiple lucent area called gyral or convolutional markings, described as resembling beaten copper, presumably resulting from increased intracranial pressure. Examination of the jaws reveals a generalized lucency of the maxilla and mandible. the cortical bone and lamina dura are thin, and the alveolar bone may be deficient. Clinical features of Hypophosphatasia include premature loss of deciduous teeth, especially incisors, hypoplasia or aplasia of root cementum, enamel hypoplasia, irregular calcification of dentin, large pulp chamber, and resorption of marginal alveolar bone and roots. Our report involves a patient with a chief complaint of early loss of both Mx. and Mn. deciduous incisors. After conducting a through clinical and radiographic examination this patient was referred to pediatrics under the suspicion of hypophosphatasia, the diagnosis proved to be correct and successful results were accomplished through a denture made to improve esthetics and function.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.19 no.1
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• pp.12-19
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• 2019

Purpose: Isolated methylmalonic acidemia (MMA) is an autosomal recessive inherited disorder of propionate metabolism. There are two subtypes of MMUT gene defects. $Mut^0$ represents complete loss of methylmalonyl-CoA mutase (MCM) activity while mut- is associated with residual MCM activity, which can be stimulated by hydroxocobalamin (OHCbl) supplementation. The objective of this study is to investigate cobalamin responsiveness and mutations present in Korean MMA population. Methods: We evaluated 10 MMA patients using somatic cell complementation analysis on their fibroblasts to measure MCM activity and vitamin B12 responsiveness for the optimal treatment. MMUT gene was sequenced to identify the MMA mutations. Results: For all patients, the incorporation of $[^{14}C]-propionate$ was low, and there was no response to OHCbl. The incorporation of $[^{14}C]-methyltetrahydrofolate$ and $[^{57}Co]-CNCbl$ fell within the normal range. There was adequate synthesis of methylcobalamin while the synthesis of adenosylcobalamin was low. The complementation analysis showed all patients were $mut^0$. The sequence analysis identified 12 different MMUT mutations, including 2 novel mutations, p.Gln267Ter and p.Ile697Phe, were identified. All the patients in this study had neonatal onset of symptoms, belonged to $mut^0$ complementation class, and as a result, showed no cobalamin responsiveness. Conclusion: No Korean MMA patient showed cobalamin responsiveness.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.1
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• pp.1-8
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• 2015

Purpose: 3-methylcrotonyl CoA carboxylase deficiency (3MCCD) is leucine metabolic disorder caused by mutation in MCCC1 or MCCC2 gene. Clinical manifestations are variable, ranging from fatal neonatal onset to asymptomatic individuals. There is no retrospective study of Korean patients undergoing long-term treatment for 3MCCD. We reported this study to find out clinical symptoms and gene analysis of 3MCCD patients. Methods: This study was based on data of patients diagnosed with 3MCCD in Soonchunhyang university hospital between April 2009 and September 2013. We report clinical, enzymatic and mutation data of 3MCCD patients found by newborn screening. Results: In tandem mass spectrometry, 3-OH-isovalerylcarnitine (C5OH) of all patients increased. And all 7 patients were elevated 3-methylcrotonylglycine (3MCG) and 3-hydroxyisovaleric acid (3HIVA) in urine. MCCC mutation was identified in 2 patients and MCCC2 was mutated in 5 patients. We found mutation occurred in 8 different parts of nucleotide and such mutation caused 7 different types of changes in amino acid. All patients are on medication of L-carnitine and L-glycine. 4 patients are taking biotin. And 4 patients are eating leucine free formula. After starting treatment, there were no significant changes of urine 3MCG and 3HIVA levels. Conclusions: According to our data, MCCC2 gene mutation was more common than MCCC1 gene mutation. But the level of 3HIVA or 3MCG in urine has no correlation with phenotype. All patients has no symptoms and are shown normal development.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.20 no.2
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• pp.55-62
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• 2020

A 22-month-old girl who had taken iron supplements due to iron deficiency anemia, presented bloody mucoid stool for one month. She had a bruise at the right periorbital area due to minor trauma and hepatosplenomegaly. Laboratory studies showed anemia, thrombocytopenia, elevated alkaline phosphatase (ALP), hypophosphatemia, decreased haptoglobin, hypocomplementemia, negative direct/indirect Coomb's test, normal vitamin D3 level and high PTHi. Wrist x-ray showed no signs of rickets. The abdominal ultrasound showed only accessory spleen. Tandem mass spectrometry was normal. During follow up, bloody stool regressed after seven days of withdrawal of iron supplement and cow milk, and the total CO2 level had been within 15-20 mEq/L with normal anion gap. NGS (next generation sequencing) panel test for evaluation of renal tubular acidosis showed negative results. After low dose steroid and vitamin D supplements under the impression of hypocomplementemic vasculitis, thrombocytopenia, C3/C4, decreased haptoglobin, and elevated ALP level became normal. At 57 months of age, laboratory findings showed elevated liver enzyme, ALP and gamma-glutamyl transferase again. And liver cirrhosis with splenomegaly and diffuse renal disease were reported with abdomen CT scan. Liver biopsy reported macro- and micronodular cirrhosis. Urine organic acid profile showed elevated succinylacetone level. Whole exome sequencing revealed novel compound heterozygous mutations (NM_00137.2:c.107T>C, NM_00137, 2:c.614T>C) in FAH gene and confirmed by Sanger sequencing. Consequently, the patient was diagnosed as chronic hereditary tyrosinemia type I. She started low phenylalanine/tyrosine diet and nitisinone treatment. Our case had presented symptoms very slowly, which is the first case of chronic tyrosinemia type I in South Korea.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.15 no.1
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• pp.45-49
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• 2019

Bartter syndrome is an inherited renal tubular disorder characterized by hypokalemia, hypochloremic metabolic alkalosis, hyperreninemia, hyperprostaglandinism, and normal blood pressure. Bartter syndrome is classified by neonatal and classic type. Clinical manifestation of Bartter syndrome considered in dental treatment include tendency to dehydration, vomiting and erosion, attrition and abrasion of the teeth. A 2-year-4 month old boy with Bartter syndrome type III was referred to the Seoul National University Dental Hospital for dental evaluation and treatment. He showed hypokalemic hypochloremic metabolic alkalosis and had been treated with indomethacin and potassium chloride. He had hypocalcified teeth with or without multisurface caries lesions in all dentition and the erosion of maxillary teeth was detected. Dental procedure under general anesthesia was scheduled due to multiple caries and his medical condition. The dental procedure was successfully performed. This case suggests that electrolyte imbalances need to be treated prior to dental treatment and complete coverage restoration is necessary to protect the eroded teeth. An appropriate management plan for the patients with Bartter syndrome should include considerations of the need for close interaction with the pediatrician for pre- and post-operative care. General anesthesia may be recommendable to manage the patients having multiple caries with Bartter syndrome.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.2
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• pp.48-54
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• 2017

Purpose: Fukuyama congenital muscular dystrophy (FCMD) is a rare, autosomal-recessive disorder characterized by early-onset hypotonia associated with brain malformations in dystroglycanopathy. Although the wide spectrum of congenital muscular dystrophies causes difficulty in diagnosis, correlating the genotype with the clinical phenotype can help diagnose FCMD. Here, we evaluated the correlation of targeted molecular genetic analysis of FKTN gene mutation with the FCMD phenotype. Methods: This study was conducted retrospectively with 9 subjects. Inclusion criteria included clinical symptoms characterized by early-onset hypotonia with magnetic resonance imaging (MRI) featuring brain malformations. FKTN gene-alteration analysis was performed using various FKTN gene-analysis methods, including sequencing. Results: Among the 9 subjects studied, 4 (44.4%) were male and 5 (55.6%) were female. The median age of onset of the first symptom was 3.1 months. The first symptom was a delayed milestone in 6 cases (66.7%). All 9 subjects (100%) presented with early-onset hypotonia and global delayed development. All subjects presented with cortical malformation in their brain MRIs. Of the 9 subjects, 6 subjects had previously undergone muscle biopsy and 4 cases (4/6; 66.7%) showed dystrophic or myopathic features. Pathogenic mutations causing FCMD were identified in 3 cases. Conclusions: In this study, all 3 subjects with FKTN mutations showed important MRI findings (pachygyria and cerebellar dysplasia). These data suggest that patients with characteristic phenotypes who show pachygyria and cerebellar abnormalities in brain MRIs may have a high probability of being diagnosed with FCMD.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.3
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• pp.92-95
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• 2017

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by an ${\alpha}$-galactosidase A (GLA, MIM 300644) enzyme deficiency due to pathogenic variants in the ${\alpha}$-galactosidase A gene (GLA). The disease leads to accumulation of globotriaosylceramide (Gb3) and related glycophospholipids affecting nearly all major organ systems, with the primary sites damaged by Gb3 including renal glomeruli, myocardium, neurons of the dorsal ganglion and autonomic nervous system, and vascular endothelial and smooth muscle. Progressive deposition in these organ systems present with various clinical manifestations including acroparesthesia, renal failure and heart failure. Here, we report a Chinese male diagnosed with Fabry disease in his late $4^{th}$ decades showing improvement of acroparesthesia during enzyme replacement therapy (ERT). A 48-year-old Chinese man who presented with chronic recurrent severe burning pain in his fingers and toes since the age of 10, with worse involvement of the former visited to our clinic for further evaluation. His medical history included a transient ischemic attack aged 40 and diagnosed with stage 4-5 chronic kidney disease aged 47. In the family history, the patient's brother was found to be have Fabry disease 1 month before his visit. Except for his brother, all other members of the family are healthy. Based on his medical history and family history, he was strongly suspicious for Fabry disease. He was found to have a galactose-alpha-1,3-galactose level 4.96 (Reference range, 42.5-67.9) suggestive of Fabry disease. The followed sequencing of GLA coding region in our patient revealed hemizyosity for the mutation c.988C>T (Q330X) in Exon 7. Since ERT start, he showed significant improvement in his symptoms of burning sensation of fingers and toes. On the contrary, due to deteriorating kidney function even with ERT, he is considered for kidney transplantation. Despite of diagnostic delay until late 4th decades, ERT showed a potential improvement of acroparesthesia in our patient. However, late start of ERT can lead to poor outcome in multiorgan function. Therefore, early diagnosis with high index of suspicion followed by continuous ERT with regular monitoring have an impact on quality of life in Fabry disease.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.3
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• pp.103-108
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• 2017

Kabuki syndrome is a rare congenital disorder that causes multiple birth defects and mental retardation. Mutation of the lysine methyltransferase 2D (KMT2D) gene is the primary cause of Kabuki syndrome. We report a 4-year-old Korean girl diagnosed with Kabuki syndrome based on distinctive facial features (eversion of the lower lateral eyelid, arched eyebrows, depressed nasal tip, prominent ears), skeletal anomalies, short stature, and molecular analysis, which revealed a novel frameshift mutation in the KMT2D gene. A 4-year-old patient had a past history of congenital cardiac malformations (coarctation of the aorta, ventricular septal defect, atrial septal defect, patent ductus arteriosus), subclinical hypothyroidism and dysmorphic features at birth including webbed neck, short fingers, high arched palate, micrognathia and horseshoe kidney. She showed unique facial features such as a long palpebral fissure, long eyelashes, arched eyebrows with sparseness of the lateral third, broad nasal root, anteverted ears, and small mouth. Her facial features suggested Kabuki syndrome, and genetic analysis discovered a novel heterozygous frameshift mutation (c.4379dup, p.Leu1461Thrfs*30) in exon 15 of the KMT2D gene. The diagnosis of our 4-year-old patient was made through thorough physical examination and history taking, and genetic testing. It is challenging to diagnose patients with Kabuki syndrome at birth, since the characteristic facial features are expressed gradually during growth. Clinical suspicion aroused by regular follow-ups may lead to earlier diagnosis and interventions.