• 대한유전성대사질환학회지
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• 제13권1호
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• pp.30-36
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• 2013

6-pyruvoyltetrahydropterin synthase (PTPS) deficiency is autosomal recessive disorder and the most common type of tetrahydrobiopterin (BH4) deficiency. It is caused by deficiency of PTPS, a cofactor involved in the biosynthesis of BH4 from guanosine triphosphate (GTP). Unlike classical phenylketonuria, which needs restriction of dietary phenylalanine for whole life, BH4 deficiency is treated by tetrahydrobiopterin, levodopa, and 5-hydroxytryptophan replacement. So it is important to make accurate diagnosis and initiate treatment as soon as possible for a better prognosis. There is no retrospective study of Korean patients undergoing long-term treatment for PTPS deficiency. We report 9 Korean patients with PTPS deficiency and their laboratory findings including BH4 loading tests, urine pterin tests, genotypes, dihydropteridine reductase (DHPR) activities and clinical manifestations including medication and developmental delay existence.

• The Korean Journal of Physiology and Pharmacology
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• 제14권3호
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• pp.177-183
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• 2010

Tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthase (NOS) activity, is known to play important roles in modulating both NO and superoxide production during vascular diseases such as atherosclerosis. However, the role of BH4 in functions of vascular smooth muscle cells is not fully known. In this study, we tested the effects of BH4 and dihydrobiopterin (BH2), a BH4 precursor, on migration and proliferation in response to platelet-derived growth factor-BB (PDGF-BB) in rat aortic smooth muscle cells (RASMCs). Cell migration and proliferation were measured using a Boyden chamber and a 5-bromo-2'-deoxyuridine incorporation assay, respectively, and these results were confirmed with an ex vivo aortic sprout assay. Cell viability was examined by 2,3-bis [2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide assays. BH4 and BH2 decreased PDGF-BBinduced cell migration and proliferation in a dose-dependent manner. The inhibition of cell migration and proliferation by BH4 and BH2 was not affected by pretreatment with $N^G$-nitro-L-arginine methyl ester, a NOS inhibitor. Moreover, the sprout outgrowth formation of aortic rings induced by PDGF-BB was inhibited by BH4 and BH2. Cell viability was not inhibited by BH4 and BH2 treatment. The present results suggest that BH4 and BH2 may inhibit PDGF-stimulated RASMC migration and proliferation via the NOS-independent pathway. Therefore, BH4 and its derivative could be useful for the development of a candidate molecule with an NO-independent anti-atherosclerotic function.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2005년도 춘계학술대회
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• pp.53-60
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• 2005

Parkinson's disease (PD) is a progressive neurodegenerative disorder affecting $1\%$ of the population above the age of 65 and is characterized by a selective loss of dopaminergic neurons in the substantia nigra pars compacta. Although the underlying cause of dopaminergic cell death or the mechanism by which these cells degenerate is still not clearly understood, oxidative stress, mitochondrial dysfunction, and protein misfolding are thought to play important roles in the dopaminergic degeneration in PD. Tetrahydrobiopterin (BH4) is synthesized exclusively in the monoaminergic, including dopaminergic, cells and serves as an endogenous and obligatory cofactor for syntheses of the potential oxidative stressors dopamine and nitric oxide. In addition to its contribution toward the syntheses of these two potentially toxic molecules, BH4 itself can directly generate oxidative stress. BH4 undergoes oxidation during the hydroxylation reaction as well as nonenzymatic autooxidation to produce hydrogen peroxide and superoxide radical. We have previously suggested BH4 as an endogenous molecule responsible for the dopaminergic neurodegeneration. BH4 exerts selective toxicity to dopamine-producing cells via generation of oxidative stress, mitochondrial dysfunction, and apoptosis. BH4 also induces morphological, biochemical, and behavioral characteristics associated with PD in vivo. BH4 as well as enzyme activity and gene expression of GTP cyclohydrolase I, the rate-limiting enzyme in BH4 synthesis pathway, are readily upregulated by cellular changes such as calcium influx and by various stimuli including stress situations. This points to the possibility that cellular availability of BH4 might be increased in aberrant conditions, leading to increased extracellular BH4 subsequent degeneration. The fact that BH4 is specifically and endogenously synthesized in dopaminergic cells, Is readily upregulated, and generates oxidative stress-related cell death provides physical relevance of this molecule as an attractive candidate with which to explain the mechanism of pathogenesis of PD.

• The Korean Journal of Physiology and Pharmacology
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• 제17권1호
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• pp.89-97
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• 2013

Developing an animal model for a specific disease is very important in the understanding of the underlying mechanism of the disease and allows testing of newly developed new drugs before human application. However, which of the plethora of experimental animal species to use in model development can be perplexing. Administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a very well known method to induce the symptoms of Parkinson's disease in mice. But, there is very limited information about the different sensitivities to MPTP among mouse strains. Here, we tested three different mouse strains (C57BL/6, Balb-C, and ICR) as a Parkinsonian model by repeated MPTP injections. In addition to behavioral analysis, endogenous levels of dopamine and tetrahydrobiopterin in mice brain regions, such as striatum, substantia nigra, and hippocampus were directly quantified by liquid chromatography-tandem mass spectrometry. Repeated administrations of MPTP significantly affected the moving distances and rearing frequencies in all three mouse strains. The endogenous dopamine concentrations and expression levels of tyrosine hydroxylase were significantly decreased after the repeated injections, but tetrahydrobiopterin did not change in analyzed brain regions. However, susceptibilities of the mice to MPTP were differed based on the degree of behavioral change, dopamine concentration in brain regions, and expression levels of tyrosine hydroxylase, with C57BL/6 and Balb-C mice being more sensitive to the dopaminergic neuronal toxicity of MPTP than ICR mice.

• Journal of Genetic Medicine
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• 제6권2호
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• pp.170-174
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• 2009

저자들은 생후 3개월에 전형적인 페닐케톤뇨증으로 진단받고 식사요법을 유지하였으나 지연된 발달 소견 및 지능 저하를 보이고 경련 증상이 있었던 9세 남자 환아에서 효소 검사와 유전자분석으로 dihydropterine reductase (DHPR) 결핍증을 진단하였다. 그리고 $BH_4$, 신경전달물질 전구체 투여 및 엽산 보충으로 DHPR 결핍증을 치료한 1례를 경험하였기에 문헌고찰과 함께 보고한다.

• 대한유전성대사질환학회지
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• 제15권3호
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• pp.118-126
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• 2015

Background and objectives: A deficiency of BH4 (tetrahydrobiopterin) not only causes the classical phenylketonuric phenotype, but also is the source of neurological signs and symptoms due to impaired syntheses of L-Dopa and serotonin. The treatment of BH4 deficiency usually consists of replacement with BH4 and the neurotransmitters. We performed this study to finding out long-term follow-up clinical symptoms and prognosis of BH4 deficiency. Methods: Clinical and biochemical, genetic analysis were done retrospectively from January 1999 to July 2015 in Soonchunhyang University Hospital. Results: In our study, total 207 patients were confirmed to hyperphenylalaninemia. Among them, 10 patients were BH4 deficiency. 9 patients were 6-pyruvoyl-tetrahydropterin (PTPS) deficiency and one patient was dihydropteridine reductase (DHPR) deficiency. The patients who received delayed treatment, most of our patients suffered from severe psychomotor retardation, hypotonia and seizure. c.259C>T mutation was identified most commonly in PTPS gene analysis. A patient with DHPR deficiency had a mental retardation, dystonia, seizure. His seizure semiology was dialeptic feature. His EEG showed generalized spike wave patterns. All patients had treated with tolerate L-Dopa, BH4 and 5-hydroxytryptophan. Most of the early treated patients have a good tolerance for drugs well. But some patients had neurologic symptoms, despite early detection and treatment. Conclusion: BH4 deficiency patients who had delayed treatment tend to have severe psychomotor problem and neurologic deficits.

• 대한유전성대사질환학회지
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• 제13권2호
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• pp.104-110
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• 2013

Purpose: Phenylketonuria (PKU) is the first inherited metabolic disease of which treatment is known. We performed this study to find out clinical symptoms and prognosis of tetrahydrobiopterin (BH4) responsive PKU patients and genetic relation. Methods: Clinical, biochemical, genetic analysis were done retrospectively in 23 patients diagnosed BH4 responsive PKU in Soonchunhyang University Hospital from March 2000 to September 2012. Results: Patients were classified to mild hyperphenylalaninemia and mild phenylketonuria with initial plasma phenylalanine level below 20 mg/dL. After BH4 loading, blood phenylalanine decrease level ranged between 37% and 99%. Initial treatment with low phenylalanine formula or BH4 was started before 2 month after birth except 2 patients. And one of them resulted in developmental delay in language and social activity. The others showed satisfactory progress without developmental delay. In genetic analysis, of 46 allele, R241C allele mutation was identified most commonly (41%). R241C/A259T, R241C/R243Q, R241C/V388M, R241C/T278I was detected in 5 (21.7%), 3 (13%), 2 (8%), 2 (8%) patients, respectively. Conclusion: R241C mutation was detected most frequently in this study group and R243Q mutation which is known to be prevalent in Korean PKU patients was found in 4 patients (8.6%). Early diagnosis and treatment is important in PKU patients.

• Journal of Genetic Medicine
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• 제17권1호
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• pp.34-38
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• 2020

The term dopa-responsive dystonia (DRD) is used to describe a group of neurometabolic disorders, which are characterized by dystonia, and are typically associated with diurnal fluctuations and respond to levodopa treatment. Autosomal dominant DRD (DYT5a, MIM# 128230) is caused by a heterozygous mutation in the GTP cyclohydrolase 1 (GCH1) gene (MIM# 600225). GCH1 encodes an enzyme, which is involved in the biosynthesis of tetrahydrobiopterin, an essential co-factor for tyrosine hydroxylase. Herein, we report the case of a 16-year-old girl who was diagnosed with DYT5a. She exhibited additional unusual clinical features, including intellectual disability, depression, multiple skeletal anomalies, and short stature, which are not commonly observed in patients with DYT5a. The patient harbored a heterozygous missense variant, c.539A>C, p.Gln180Pro, in the GCH1 gene, which was identified by targeted gene panel analysis using next-generation sequencing.

• 대한유전성대사질환학회지
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• 제20권2호
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• pp.37-43
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• 2020

페닐케톤뇨증(PKU)은 전세계적으로 가장 잘 알려지고 중요한 유전성 대사질환이다. 1950년대 이후 단백제한을 이용한 식사치료를 처음으로 시도하여 성과가 있었던 질환이며 1960년대 이후 신생아선별검사를 통해 조기진단과 조기치료가 가능하게 된 최초의 유전성대사질환이기 때문이다. 단백제한 식사치료의 효과가 좋지만 학동기, 사춘기 이후 성인시기까지 유지하는 것의 어려움이 있고 이시기에 조절이 잘 되지 않았을 경우 경련, 여러가지 정신과적인 문제들, 삶의 질의 감소 등이 문제가 되어서 오랜 기간 치료를 위한 여러 방법들이 제시되었다. 더해서 2014년 미국의학유전학회(American Medical College of Medical Genetics and Genomics, ACMG)에서 전 연령에서 혈중 페닐알라닌 수치를 120-360 umol/L로 제시를 한 이후 더욱 치료의 중요성이 올라갔다. 2000년대 페닐알라닌수산화 효소(phenylalanine hydroxylase, PAH)의 조효소인 tetrahydrobiopterin (BH4)가 치료 승인되어서 약물반응을 보이는 환자에서 치료가 시작되었으며 4세미만에서도 허가가 되어서 이른 시기부터 약물치료를 병행하여 효과를 보게 되었다. 높은 혈중 페닐알라닌수치가 혈액-뇌 장벽(Blood-brain barrier, BBB)을 통하여 뇌로 넘어가서 회백질의 변성을 나타내게 되는 문제를 막기 위해 거대중성아미노산(LNAA)를 이용한 치료가 시도되고 있다. 오랫동안 연구되었던 페닐알라닌을 trans-cinnamic acid와 암모니아로 변화를 시키는 phenylalanine ammonialyase (PAL)을 이용한 효소치료는 최근 약제로 개발되어서 2018년 이후 성인환자를 대상으로 치료가 시작되었고 잘 조절되지 않는 환자들에게 효과를 보이고 있다. PAL을 경구용으로 개발하는 것이 빠르게 진행 중이며 유전자치료에 대한 연구들도 활발하게 진행이 되고 있어 다양한 치료들이 앞으로 기대된다.

• Molecules and Cells
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• 제27권5호
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• pp.583-589
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• 2009

GTP cyclohydrolase I (GTPCH) is a key enzyme in the de novo synthesis of tetrahydrobiopterin. Previously, the Drosophila melanogaster GTPCH gene has been shown to be expressed from two different promoters (P1 and P2). In our study, the 5'-flanking DNA regions required for P1 and P2 promoter activities were characterized using transient expression assay. The DNA regions between -98 and +31, and between -73 and +35 are required for efficient P1 and P2 promoter activities, respectively. The regions between -98 and -56 and between -73 and -41 may contain critical elements required for the expression of GTPCH in Drosophila. By aligning the nucleotide sequences in the P1 and P2 promoter regions of the Drosophila melanogaster and Drosophila virilrs GTPCH genes, several conserved elements including palindromic sequences in the regions critical for P1 and P2 promoter activities were identified. Western blot analysis of transgenic flies transformed using P1 or P2 promoter-lacZ fusion plasmids further revealed that P1 promoter expression is restricted to the late pupae and adult developmental stages but that the P2 promoter driven expression of GTPCH is constitutive throughout fly development. In addition, X-gal staining of the embryos and imaginal discs of transgenic flies suggests that the P2 promoter is active from stage 13 of embryo and is generally active in most regions of the imaginal discs at the larval stages.