• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.1
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• pp.47-51
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• 2016

Propionic acidemia (PA) is an autosomal recessively inherited disorder of the organic acid metabolism. It is caused by a deficiency of propionyl-CoA carboxylase (PCC). PCC is a heteropolymeric enzyme composed of ${\alpha}$- and ${\beta}$-subunits. The clinical symptoms of PA are heterogeneous and present vomiting, dehydration, hypotonia, and lethargy, and it can result in death. The typical presentations of neonatal onset PA are life-threatening metabolic acidosis and hyperammonemia. Here, we described a case of neonatal onset PA with mild clinical presentations. She was born to a healthy mother without complications. No significant illness was observed until nine days after birth. She started exhibiting poor oral feeding, vomiting, lethargy, and hypotonia at ten days old. Her laboratory results showed mild hyperammonemia and acidosis. The initial diagnosis was neonatal sepsis and she was treated with antibiotics. However, her clinical symptoms didn't improve. So we considered a metabolic disease. She was given nothing by mouth and intravenous hydration and nutrition support was performed. Propionylglycine and 3-hydroxypropionic acid were showed high concentrations in urine by gas chromatograph mass spectrometry (GC-MS). C3 level of acylcarnitine analysis elevated 10.4 uM/L (range, 0.200-5.00) in plasma. We took gene analysis for PA to be based on the symptoms and laboratory results. We detected PCCB gene mutation and diagnosed PA. She survived without severe neurologic defects and complications and was hospitalized only three times with upper respiratory tract infections for 7 years. We report a case of a ten days old neonate with PA presenting without severe metabolic acidosis and hyperammonemia who was effectively treated with early aggressive care and conventional methods.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.2
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• pp.93-97
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• 2015

Short-chain acyl-CoA dehydrogenase (SCAD) deficiency is an autosomal recessive hereditary metabolic disorder of mitochondrial fatty acid beta-oxidation. Mutations in the ACADS gene cause short-chain acyl-CoA dehydrogenase deficiency, which is characterized by developmental delay, hypotonia, seizure, and hypoglycemia. Here, we describe one Korean pediatric case of SCAD deficiency, which was diagnosed during newborn screening by tandem mass spectrometry and confirmed by molecular analysis. The level of C4 was typically elevated 5.23 mg/dL (reference range <1.5 mg/dL). This patient had a homozygous mutation [c.1031A>G, p. E344G] in ACADS. Therefore, we present a case of SCAD deficiency in an otherwise healthy neonate and her subsequent development and growth over four years.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.14 no.1
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• pp.66-70
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• 2014

X-linked adrenoleukodystrophy (ALD) is a uncommon metabolic disorder which derived by peroxismal ${\beta}$-oxidation and elevation of serum very long chain fatty acid (VLCFA). VLCFA is mainly accumulated in the myelin of the central nervous system and adrenal cortex, by which the expressed symptoms of this disease are mainly neurologic and endocrinologic (such as adrenal insufficiency). The mutations in the ABCD1 gene causes X-linked ALD, nevertheless its phenotypes and genotypes are poorly coordinated. We report the case of a 12-year-old boy with X-linked ALD who developed vomiting, fatigue and poor oral intake. Severe dehydration and hyponatremia were found in initial physical examination and laboratory test, but his motor/sensory nerve function and mental status were completely normal. We diagnosed ALD with diffuse high-intensity signal in both parietotemporal cerebellar white matter in brain MRI and elevated serum VLCFA. Later, we confirmed a novel c.1635-1G>A (IVS6-1G>A) mutations of the ABCD1 gene. With the discrepancy between its phenotypes and genotypes, various phenotypes could be seen in X-ALD patient. Careful examination and further studies for these patients will be needed.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.3 no.1
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• pp.86-93
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• 2003

Background : The SCL began screening of newborns and high risk group blood spots with tandem mass spectrometry (MS/MS) in April 2001. Our goal was to determine approximate prevalence of metabolic disorders, optimization of decision criteria for estimation of preventive effect with early diagnosis. This report describes the ongoing effort to identify more than 30 metabolic disorders by MS/MS in South Korea. Methods : Blood spot was collected from day 2 to 30 (mostly from day 2 to 10) after birth for newborn. Blood spot of high risk group was from the pediatric patients in NICU, developmental delay, mental retardation, strong family history of metabolic disorders. One punch (3.2 mm ID) of dried blood spots was extracted with $150{\mu}L$ of methanol containing isotopically labelled amino acids (AA) and acylcarnitines (AC) internal standards. Butanolic HCl was added and incubated at $65^{\circ}C$ for 15 min. The butylated extract was introduced into the inlet of MS/MS. Neutral loss of m/z 102 and parent ion mode of m/z 85 were set for the analyses of AA and AC, respectively. Diagnosis was confirmed by repeating acylcarnitine profile, urine organic acid and plasma amino acid analysis, direct enzyme assay, or molecular testing. Results : Approximately 31,000 neonates and children were screened and the estimated prevalence (newborn/high risk group), sensitivity, specificity and recall rate amounted to 1:2384/1:2066, 96.55%, 99.98%, and 0.73%, respectively. Confirmed 28 (0.09%) multiple metabolic disorders (newborn/high risk) were as follows; 13 amino acid disorders [classical PKU (3/4), BH4 deficient-hyperphenylalaninemia (0/1), Citrullinemia (1/0), Homocystinuria (0/2), Hypermethioninemia (0/1), Tyrosinemia (1/0)], 8 organic acidurias [Propionic aciduria (2/1), Methylmalonic aciduria (0/1), Isovaleric aciduria (1/1), 3-methylcrotonylglycineuria (1/0), Glutaric aciduria type1 (1/0)], 7 fatty acid oxidation disorders [LCHAD def. (2/2), Mitochondrial TFP def. (0/1), VLCAD def. (1/0), LC3KT def. (0/1). Conclnsion : The relatively normal development of 10 patients with metabolic disorders among newborns (except for the expired) demonstrates the usefulness of newborn screening by MS/MS for early diagnosis and medical intervention. However, close coordination between the MS/MS screening laboratory and the metabolic clinic/biochmical geneticists is needed to determine proper decision of screening parameters, confirmation diagnosis, follow-up scheme and additional tests.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.2
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• pp.109-114
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• 2016

Carbamoyl phosphate synthetase 1 (CPS1) deficiency is an autosomal recessive urea cycle disorder which causes hyperammonemia. CPS1 is the first enzyme step in the urea cycle and almost patients present their symptoms during neonatal period. We report a case of CPS1 deficiency in a boy who developed symptoms including lethargy and seizure at 3 days of age. The ammonia level was up to $2,325{\mu}mol/L$, sodium benzoate (250 mg/kg/d) and high calories of both dextrose and lipid was promptly administered. Central access by experienced pediatric surgeon and emergent continuous hemodialysis by pediatric nephrologist was performed within 3 hours and ammonia was less than $100{\mu}mol/L$ at 5 days of age. Currently, he has showed excellent response to treatments including scavenging drugs and a low-protein diet. Despite of diffuse increasing signal intensity on cerebral white matters and basal ganglia on brain MRI, his development and weight gain were good at the last follow-up at 11 months of age. Molecular assay of the CPS1 gene demonstrated that patient had compound heterozygous for c.1529del ($p.Gly510Alafs^*5$) in exon 14 and c.3142-1G>C (IVS25(-1)G>C) in intron 25 and exon 26 boundary. The splicing mutation was novel mutation and inherited from patient's mother. Here, we report a neonatal lethal type CPS1 deficiency patient having novel mutation.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.3
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• pp.148-154
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• 2016

A urea cycle disorder is a condition caused by a defect of the enzymes in the urea cycle, and deficiency of ornithine transcarbamylase (OTC), which converts carbamoyl phosphate and ornithine into citrulline, is the most common type of the disorder. OTC deficiency induces the accumulation of precursors of urea, ammonia, and glutamine, leading to neurological symptoms including hypotonia, respiratory failure, seizure, lethargy, and coma and sometimes to death. Because OTC deficiency is inherited in an X-linked manner, typical symptoms such as vomiting, poor feeding, and lethargy appear mainly in male neonates. We recently had a case that presented with neonatal onset lethargy, vomiting, and apnea in a 4-day-old boy. He was diagnosed with OTC deficiency by biochemical phenotype, including hyperammonemia and an increased orotic acid level in the urine. Genetic analysis of the OTC gene showed a novel mutation c.780_781insCAGGCAGTGT (p.Ile261Glnfs*35). He was treated for hyperammonemia using continuous venovenous hemofiltration (CVVH) at 118 hours after birth. After 4 days of CVVH, his consciousness and blood ammonia concentration were normalized, and he was discharged at the age of 53 days. At around 12 months of age, bilateral femur fractures and osteomyelitis occurred in this patient. Two months after the fracture, he died of septic shock, insulin-resistant hyperglycemia, and multi-organ failure.

• Journal of Genetic Medicine
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• v.4 no.1
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• pp.53-63
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• 2007

Purpose : Tandem mass spectrometry (MS/MS) is effective screening test for inherited metabolic diseases. In this study, we estimate potential costs and benefits of using tandem mass spectrometry (MS/MS) to screen new borns for inherited metabolic diseases (phenylketonuria, BH4 deficiency, citrullinemia, maple syrup urine disease, propionic aciduria, isovaleric aciduria, glutaric aciduria type 1, LCHAD deficiency) in Korea. Methods : From April 2001 to March 2004, 79,179 new borns were screened for amino acid disorders, organic acid disorders, and fatty acid oxidative disorders. Twenty-eight new borns were diagnosed with one of the metabolic disorder and the collective estimated prevalence amounted to 1 in 2,800 with a sensitivity of 97.67%, a specificity of 99.28%, a recall rate of 0.05%, and a positive preditive value of 6.38%. We calculated and compared the total costs in case when neonatal screening on pheny lketonuria, BH4 deficiency, citrullinemia, maple syrup urine disease, propionic aciduria, isovaleric aciduria, glutaric aciduria type 1, LCHAD deficiency is implemented, and when not. Results : If the neonatal screening on pheny lketonuria, BH4 deficiency, citrullinemia, maple syrup urine disease, propionic aciduria, isovaleric aciduria, glutaric aciduria type 1, LCHAD deficiency is implemented, total benefits far exceed costs at a ratio of 1.40:1. Conclusion : Although, this study only concerns the monetary aspects of the neonatal screening, tandem mass spcetrometry for neonatal screening is cost-effective compared with not screening. The study appears to support the introduction of tandem mass spectrometry into a Korea neonatal screening programme for inherited metabolic diseases.

• Clinical and Experimental Pediatrics
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• v.49 no.11
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• pp.1125-1139
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• 2006

In 1991, the Ministry of Health & Social affairs adopted a nationwide service program for neonatal screening of phenylketonuria, galactosemia, maple syrup urine disease, homocystinuria, histidinemia & congenital hypothyroidism for newborns delivered from low class pregnant women registered in health centers. Government decreased the test items from six to two, PKU & congenital hypothyroidism to increase test numbers with same budget from 1995. Government decided to test PKU & hypothyroidism for all newborns from 1997. 78 laboratories wanted to participate for neonatal screening test in 1999. Government didn't decide laboratory center for a certain district and placed responsibility on free competition. Government are planning to test 573,000 newborns from 1998, Government decided to screen 6 items PKU, congenital hypothyroidism, maple syrup urine disese, homocystinuria, galactosemia and congenital adrenal hyperplasia from 2006. 17 laboratores are participating now. The cost of screening test is supported by both the federal government and local government on a 40-60 basis. In case a patient with an inherited metabolic disease is diagnosed by screening of government program, special milk is provided at government's expense. Interlaboratory quality control was started 6 times a year from 1994. According to the government project, 3,707,773 newborns were screened. 86 PKU, 718 congenital hypothyroidism were detected. So incidence of PKU is 1/43,114 and congenital hypothyroidism is 1/4,612. Maeil dairy company produced new special formula for PKU, MMA and PA, MSUD, urea cycle disorder, homocystinuria, isovaleric acidemia from Oct. 1999. The cost benefit of performing screening procedures coupled with treatment has been estimated to be as high as 1.77 times in PKU, 11.11 times in congenital hypothyroidism than cost without screening. We are trying to increase the budget to test all newborns for Tandem mass sereening & Wilson disease from 2008. Now it is a very important problem to decrease laboratory numbers of neonatal screening in Korea. So we are considering 4-5 central laboratories which cover all newborns and are equipped with tandem mass spectrometer & enzyme immunoassay for TSH, 17OHP & enzyme colorimetric assay for galactose.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.1 no.1
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• pp.23-27
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• 2001

Fanconi-Bickel Syndrome (FBS) is a rare autosomal recessive disorder of carbohydrate metabolism recently demonstrated to be caused by mutations in the GLUT 2 gene for the glucose transporter protein 2 expressed in liver, pancreas, intestine, and kidney. This disease is characterized by hepatorenal glycogen accumulation, both fasting hypoglycemia as well as postprandial hyperglycemia and hyperglactosemia, and generalized proximal renal tubular dysfunctions. We report the first Korean patient with FBS diagnosed based on clinical manifestations and identification of a novel mutation in the GLUT 2 gene. She was initially diagnosed having a neonatal diabetes mellitus due to hyperglycemia and glycosuria at 3 days after birth. In addition, newborn screening for galactosemia revealed hypergalactosemia. Thereafter, she has been managed with lactose free milk, insulin therapy. However, she failed to grow and her liver has been progressively enlarging. Her liver functions were progressively deteriorated with increased prothrombin time. Liver biopsy done at age 9 months indicated micronodular cirrhosis with marked fatty changes. She succubmed to hepatic failiure with pneumonia at 10 months of age. Laboratory tests indicated she had generalized proximal renal tubular dysfuctions; renal tubular acidosis, hypophosphatemic rickets, and generalized aminoaciduria. Given aforementioned findings, the diagnosis of FBS was appreciated at age of 2 months. The DNA sequencing analysis of the GLUT 2 gene using her genomic DNA showed a novel mutation at 5th codon; Lysine5 Stop (K5X).

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.3
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• pp.110-117
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• 2015

All infants should be screened for phenylketonuria (PKU) within the three days of life, in order to allow timely dietary intervention to protect children with PKU from neurologic damage in Korea. A commonly used cut-off level for diagnosis of PKU is $240{\mu}mol/L$ (4 mg/dL). Up to 2% of cases of hyperphenylalaninemias (HPA) detected by the screening test will account for a disorder of $BH_4$ metabolism. Therefore, analysis of blood or urinary pterins is essential, backed up with measurement of DHPR activity, as this allows differentiation of $BH_4$ disorders. A $BH_4$ loading test and measurement of neurotransmitters in CSF provide further important information to the severity of $BH_4$ deficiency and $BH_4$ loading test can detect patients with $BH_4$ deficiency and $BH_4$ responsive PKU. Several protocols for $BH_4$ loading test have been described, involving treatment with $BH_4$ for periods ranging from 1 day to 1 month, and using doses of $BH_4$ of 10-20 mg/kg. There is general agreement that a reduction on blood phenylalanine of at least 30% in response to $BH_4$ loading indicates a clinically significant effect, although in some tests a lower cut-off value may be defined for individual patients, or no specific cut-off value is proposed. The frequency of $BH_4$ responsiveness is highest in patients with mild HPA and mild to moderate PKU resulting from PAH mutations with residual activity.