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Xie K, Zeng B, Zhang L, Chen S, Zou Y, Yuan H, Huang S, Wang F, Lu Q, Liu Y, Yang B. Mutation spectrum of PTS gene in patients with tetrahydrobiopterin deficiency from jiangxi province. Front Genet 2022; 13:1077729. [PMID: 36583021 PMCID: PMC9792861 DOI: 10.3389/fgene.2022.1077729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 11/29/2022] [Indexed: 12/15/2022] Open
Abstract
Background: Hyperphenylalaninemia (HPA) is the most common inborn error in amino acid metabolism. It can be primarily classified into phenylalanine hydroxylase (PAH) deficiency and tetrahydrobiopterin (BH4) deficiency. BH4 deficiency (BH4D) is caused by genetic defects in enzymes involved in the biosynthesis and regeneration of BH4. 6-pyruvoyl-tetrahydropterin synthase (PTPS/PTS), which is encoded by the PTS gene, participates in the biosynthesis of BH4. PTPS deficiency (PTPSD) is the major cause of BH4D. In this study, we investigated that the prevalence of BH4D in Jiangxi province was approximately 12.5 per 1,000,000 live births (69/5,541,627). Furthermore, the frequency of BH4D was estimated to be 28.8% (69/240) in the HPA population of Jiangxi. In this study, we aimed to characterize the mutational spectrum of the PTS gene in patients with PTPSD from Jiangxi province. Method: Newborn screening data of Jiangxi province from 1997 to 2021 were analyzed and 53 families with PTPSD were enrolled for the analysis of the PTS gene variants by Sanger sequencing. Results: 106 variants were identified in 106 alleles of 53 patients with PTPSD, including 13 types of variants reported previously, and two novel variants (c.164-36A>G and c.146_147insTG). The predominant variant was c.259C>T (47.2%), followed by c.84-291A>G (19.8%), c.155A>G (8.5%), c.286G>A (6.6%) and c.379C>T (4.7%). Conclusion: The results of this study can not only provide guidance for the molecular diagnosis and genetic counseling in cases of PTPS deficiency but also enrich the PTS mutation database.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Qing Lu
- *Correspondence: Qing Lu, ; Yanqiu Liu, ; Bicheng Yang,
| | - Yanqiu Liu
- *Correspondence: Qing Lu, ; Yanqiu Liu, ; Bicheng Yang,
| | - Bicheng Yang
- *Correspondence: Qing Lu, ; Yanqiu Liu, ; Bicheng Yang,
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Sadat Fatemi SH, Eshraghi P, Ghanei M, Hamzehloei T. Genetic evaluation of hyperphenylalaninemia patients with tetrahydrobiopterin deficiency in Iranian population: Identification of four novel disease-causing variants. Mol Genet Genomic Med 2022; 10:e2081. [PMID: 36382472 DOI: 10.1002/mgg3.2081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/09/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Hyperphenylalaninemia (HPA) is the most common inborn error of amino acid metabolism worldwide. At least 2% of HPA cases are caused by a deficiency in tetrahydrobiopterin (BH4) metabolism. Genes such as QDPR and PTS are essential in the BH4 metabolism. This study aims to identify disease-causing variants in HPA patients, which may be helpful in genetic counseling and prenatal diagnosis. METHODS A total of 10 HPA patients were enrolled in this study. The coding and adjacent intronic regions of PTS and QDPR genes were examined using Sanger sequencing. Protein modeling was also performed for novel identified variants. RESULTS Ten patients and a total of 20 alleles were studied, which led to the identification of 10 different variants. All variants identified in PTS and QDPR were missense, except for the c.383_407del variant in the QDPR. Also, three novel variants were identified in the QDPR, including c.79G>T, c.383_407del and c.488G>A, and a novel variant, c.65C>G, in the PTS. CONCLUSIONS Despite the genetic similarities in the disease-causing variants, differences were observed in the Asian and European populations with our populations; As a result, similar but more extensive studies are needed to investigate the distribution of disease-causing variants in genes involved in non-PKU hyperphenylalaninemia.
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Affiliation(s)
- Seyedeh Helia Sadat Fatemi
- Medical Genetics and Molecular Medicine Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Medical Genetics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Peyman Eshraghi
- Clinical Research Development Unit of Akbar Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Ghanei
- Medical Genetics and Molecular Medicine Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Medical Genetics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Tayebeh Hamzehloei
- Medical Genetics and Molecular Medicine Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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Song B, Ma Z, Liu W, Lu L, Jian Y, Yu L, Wan Z, Yue X, Kong Y. Clinical, biochemical and molecular spectrum of mild 6-pyruvoyl-tetrahydropterin synthase deficiency and a case report. Fetal Pediatr Pathol 2021; 40:707-716. [PMID: 32202960 DOI: 10.1080/15513815.2020.1737992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Background 6-Pyruvoyl-tetrahydropterin synthase (PTS) is the key enzyme in BH4 synthesis. PTS deficiency is classified as severe type and mild type, and the prognosis and treatment differ for these types. Distinguishing between two types in the early stage is difficult. Reference to reported cases is needed for interpretation of the correlation between genotype and prognosis. Case report: We report a full-term female newborn with mild PTS deficiency. On the day 21 after birth, the phenylalanine level was 859.6 mmol/L (reference range: 30-117 mmol/L). After 1 year of observation, the patient was found to be in a healthy condition without treatment. Conclusions: Although the phenylalanine level is high in mild PTS deficiency patients after birth, some of them may have few symptoms with no treatment. We review 19 cases and find 8 mutations of PTS that may be associated with mild PTS deficiency.
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Affiliation(s)
- Boyan Song
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Zhijun Ma
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Wei Liu
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Lihong Lu
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Yongjian Jian
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Lu Yu
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Zhihui Wan
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Xiaofei Yue
- Department of Laboratory Medicine, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Yuanyuan Kong
- Newborn Screening Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
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Himmelreich N, Blau N, Thöny B. Molecular and metabolic bases of tetrahydrobiopterin (BH 4) deficiencies. Mol Genet Metab 2021; 133:123-136. [PMID: 33903016 DOI: 10.1016/j.ymgme.2021.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 01/01/2023]
Abstract
Tetrahydrobiopterin (BH4) deficiency is caused by genetic variants in the three genes involved in de novo cofactor biosynthesis, GTP cyclohydrolase I (GTPCH/GCH1), 6-pyruvoyl-tetrahydropterin synthase (PTPS/PTS), sepiapterin reductase (SR/SPR), and the two genes involved in cofactor recycling, carbinolamine-4α-dehydratase (PCD/PCBD1) and dihydropteridine reductase (DHPR/QDPR). Dysfunction in BH4 metabolism leads to reduced cofactor levels and may result in systemic hyperphenylalaninemia and/or neurological sequelae due to secondary deficiency in monoamine neurotransmitters in the central nervous system. More than 1100 patients with BH4 deficiency and 800 different allelic variants distributed throughout the individual genes are tabulated in database of pediatric neurotransmitter disorders PNDdb. Here we provide an update on the molecular-genetic analysis and structural considerations of these variants, including the clinical courses of the genotypes. From a total of 324 alleles, 11 are associated with the autosomal recessive form of GTPCH deficiency presenting with hyperphenylalaninemia (HPA) and neurotransmitter deficiency, 295 GCH1 variant alleles are detected in the dominant form of L-dopa-responsive dystonia (DRD or Segawa disease) while phenotypes of 18 alleles remained undefined. Autosomal recessive variants observed in the PTS (199 variants), PCBD1 (32 variants), and QDPR (141 variants) genes lead to HPA concomitant with central monoamine neurotransmitter deficiency, while SPR deficiency (104 variants) presents without hyperphenylalaninemia. The clinical impact of reported variants is essential for genetic counseling and important for development of precision medicine.
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Affiliation(s)
- Nastassja Himmelreich
- Center for Child and Adolescent Medicine, Dietmar-Hopp Metabolic Center, Division 1, Heidelberg, Germany
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital Zürich, Zürich, Switzerland.
| | - Beat Thöny
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland.
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Fernández-Lainez C, Ibarra-González I, Alcántara-Ortigoza MÁ, Fernández-Hernández L, Enríquez-Flores S, González-Del Ángel A, Blau N, Thöny B, Guillén-López S, Belmont-Martínez L, Ruiz-García M, Vela-Amieva M. Mutational spectrum of PTS gene and in silico pathological assessment of a novel variant in Mexico. Brain Dev 2018; 40:530-536. [PMID: 29685341 DOI: 10.1016/j.braindev.2018.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 01/23/2023]
Abstract
BACKGROUND Tetrahydrobiopterin (BH4) is the cofactor for 6-pyruvoyl-tetrahydropterin synthase (PTPS); it is involved in BH4 biosynthesis and is encoded by PTS gene. Its deficiency (PTPSD) is characterized by hyperphenylalaninemia (HPA) and deficit in central monoamine neurotransmitters. We describe the clinical and mutational spectrum of five patients with PTPSD, from four unrelated Mexican families. All patients had symptomatic diagnosis and presented severe early neurological manifestations and HPA. METHODS Clinical and biochemical data from studied patients were recorded. Responsible PTPSD genotypes was determined by direct and bidirectional Sanger DNA sequencing of the six PTS coding exons and their exon-intron borders, and these were directly searched in the available relatives. The novel PTS missense variant [NM_3000317.2:331G > T, p.(Ala111Ser)] was subjected to in silico, to predict a possible deleterious effect. RESULTS Diminished fetal movements were perceived as a uniform characteristic in the studied group. DNA sequencing showed two known p.(Arg25∗) and p.(Val132TyrFs∗19) and the novel missense p.(Ala111Ser) PTS variants, the latter representing potentially a frequent PTPSD-responsible allele (50%, 4/8) in Mexican patients. In silico protein modeling analysis of the p.(Ala111Ser) variant revealed loss of hydrophobic interactions between the alanine and neighboring valines, suggesting that these changes in polarity may be detrimental for enzyme function, structure and/or stability. CONCLUSIONS This work contributes to the knowledge of PTPS molecular spectrum. The delayed diagnosis of these patients emphasizes the importance of considering BH4 metabolism defects in the differential diagnosis of HPA, especially for countries that are beginning their HPA newborn screening programs.
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Affiliation(s)
- Cynthia Fernández-Lainez
- Laboratory of Inborn Errors of Metabolism and Screening, National Institute of Pediatrics, Mexico City, Mexico
| | - Isabel Ibarra-González
- Nutritional Genetics Unit, Biomedical Research Institute, UNAM-National Institute of Pediatrics, Mexico City, Mexico
| | | | - Liliana Fernández-Hernández
- Laboratory of Molecular Biology, Department of Genetics, National Institute of Pediatrics, Mexico City, Mexico
| | - Sergio Enríquez-Flores
- Division of Experimental Medicine, National Institute of Pediatrics, Mexico City, Mexico
| | - Ariadna González-Del Ángel
- Laboratory of Molecular Biology, Department of Genetics, National Institute of Pediatrics, Mexico City, Mexico
| | - Nenad Blau
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany
| | - Beat Thöny
- Division of Metabolism and Children's Research Centre (CRC), University Children's Hospital, Zurich, Switzerland
| | - Sara Guillén-López
- Laboratory of Inborn Errors of Metabolism and Screening, National Institute of Pediatrics, Mexico City, Mexico
| | - Leticia Belmont-Martínez
- Laboratory of Inborn Errors of Metabolism and Screening, National Institute of Pediatrics, Mexico City, Mexico
| | - Matilde Ruiz-García
- Department of Neurology, National Institute of Pediatrics, Mexico City, Mexico
| | - Marcela Vela-Amieva
- Laboratory of Inborn Errors of Metabolism and Screening, National Institute of Pediatrics, Mexico City, Mexico.
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Han B, Zou H, Han B, Zhu W, Cao Z, Liu Y. Diagnosis, treatment and follow-up of patients with tetrahydrobiopterin deficiency in Shandong province, China. Brain Dev 2015; 37:592-8. [PMID: 25304915 DOI: 10.1016/j.braindev.2014.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/05/2014] [Accepted: 09/17/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To summarize the clinical and biochemical data, mutation analysis, treatment, outcome and the follow-up data of patients with BH4 deficiency from 2004 to 2012 in Shandong province, China. METHODS We analyzed the clinical, biochemical and treatment data of 40 patients with BH4 deficiency. Urinary neopterin and biopterin were analyzed. Further BH4 loading tests were performed in suspected patients with abnormal urinary pterin profiles. The patients with BH4 deficiency were treated with BH4 and neurotransmitter after diagnosis. Blood phenylalanine level, clinical symptoms and mental development were followed up. RESULTS 40 cases with BH4 deficiency were identified and all classified as PTPS deficiency between 2004 and 2012 in Shandong province, China. They were diagnosed at the age of 20d - 41m and most patients received treatment with BH4, l-dopa and 5-HTP after diagnosis. Seven different mutations (P87S, K91R, T106M, D96N, N52S, S21R, and L127F) were detected in 11 patients. But outcome assessments were not always available. We obtained 19 records of DQ/IQ assessment. In 9 patients (7 early and 2 late diagnosed) no development delay is observed, while in 10 patients (8 early and 2 late diagnosed) development was delayed. CONCLUSIONS Our study emphasized that screening for BH4 deficiency should be carried out in all patients with HPA in order to minimize misdiagnosis. Although the outcomes of BH4 deficiency are highly variable, early diagnosis and treatment is essential for good outcomes.
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Affiliation(s)
- Bingjuan Han
- Jinan Maternal and Child Care Hospital, Jinan 250001, Shandong Province, China
| | - Hui Zou
- Jinan Maternal and Child Care Hospital, Jinan 250001, Shandong Province, China
| | - Bingchao Han
- Jinan Maternal and Child Care Hospital, Jinan 250001, Shandong Province, China
| | - Weiwei Zhu
- Jinan Central Hospital, Jinan 250013, Shandong Province, China
| | - Zhiyang Cao
- Nanjing Jiangning Hospital, Affiliated to Nanjing Medical University, Nanjing 211100, Jiangsu Province, China.
| | - Yingxia Liu
- Jinan Maternal and Child Care Hospital, Jinan 250001, Shandong Province, China; Department of Immunology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China.
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Inherited metabolic diseases in the Southern Chinese population: spectrum of diseases and estimated incidence from recurrent mutations. Pathology 2015; 46:375-82. [PMID: 24992243 DOI: 10.1097/pat.0000000000000140] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Inherited metabolic diseases (IMDs) are a large group of rare genetic diseases. The spectrum and incidences of IMDs differ among populations, which has been well characterised in Caucasians but much less so in Chinese. In a setting of a University Hospital Metabolic Clinic in Hong Kong, over 100 patients with IMDs have been seen during a period of 13 years (from 1997 to 2010). The data were used to define the spectrum of diseases in the Southern Chinese population. Comparison with other populations revealed a unique spectrum of common IMDs. Furthermore, the incidence of the common IMDs was estimated by using population carrier frequencies of known recurrent mutations. Locally common diseases (their estimated incidence) include (1) glutaric aciduria type 1 (∼1/60,000), (2) multiple carboxylase deficiency (∼1/60,000), (3) primary carnitine deficiency (∼1/60,000), (4) carnitine-acylcarnitine translocase deficiency (∼1/60,000), (5) glutaric aciduria type 2 (∼1/22,500), (6) citrin deficiency (∼1/17,000), (7) tetrahydrobiopterin-deficient hyperphenylalaninaemia due to 6-pyruvoyl-tetrahydropterin synthase deficiency (∼1/60,000), (8) glycogen storage disease type 1 (∼1/150,000). In addition, ornithine carbamoyltransferase deficiency and X-linked adrenoleukodystrophy are common X-linked diseases. Findings of the disease spectrum and treatment outcome are summarised here which may be useful for clinical practice. In addition, data will also be useful for policy makers in planning of newborn screening programs and resource allocation.
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Ye J, Yang Y, Yu W, Zou H, Jiang J, Yang R, Shang S, Gu X. Demographics, diagnosis and treatment of 256 patients with tetrahydrobiopterin deficiency in mainland China: results of a retrospective, multicentre study. J Inherit Metab Dis 2013; 36:893-901. [PMID: 23138986 DOI: 10.1007/s10545-012-9550-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 09/28/2012] [Accepted: 10/08/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND National coverage of neonatal screening for hyperphenylalaninaemia (HPA) in China is still low and tests to differentiate causes of HPA are not performed in many centres. This study aimed to describe the demographics, geographic distribution, diagnosis, treatment and clinical outcomes of treatment, including intellectual development, in patients with tetrahydrobiopterin (BH4) deficiency in mainland China. METHODS This was a retrospective, multicentre, chart review in patients with BH4 deficiency across mainland China born 1985-2010. RESULTS Two hundred fifty six patients were included; 59.9 % (267/446) of parents were from eastern China. Median (interquartile range) age at diagnosis decreased from 12.0 (5.5, 102.0) months to 2.0 (1.0, 3.5) months in patients born 1985-1999 (n = 28) and 2005-2010 (n = 152), respectively. 6-Pyruvoyl-tetrahydropterin synthase (PTPS) deficiency was the primary cause of BH4 deficiency (96.0 %); four hotspot mutations accounted for 76.6 % of PTS gene mutations; two novel variants in the QDPR gene were identified. Most patients (83.6 %) received treatment with BH4, L-dopa, 5-hydroxytryptophan and/or diet therapy. Target blood Phe concentration was confirmed at 88.9 % of visits; median (Q1, Q3) blood Phe concentration was 106.8 (73.0, 120.0) μmol/L during therapy and 117.0 (67.1, 120.0) μmol/L at last visit. Median (Q1, Q3) WISC IQ score was 80.0 (69.0, 90.0) in 33 patients. DQ scores were within normal range (≥85) for 37/59 (62.7 %) patients. Physical development indicators were within normal ranges. Treatment-related adverse events, reported in 20/256 (7.8 %) patients, were mild-to-moderate in severity. CONCLUSION This study provides valuable information on the current and historical situation of BH4 deficiency in mainland China.
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Affiliation(s)
- Jun Ye
- Xinhua Hospital affiliated to Shanghai JiaoTong University School of Medicine, Shanghai, PR China
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Mutation Profile of the MUT Gene in Chinese Methylmalonic Aciduria Patients. JIMD Rep 2012; 6:55-64. [PMID: 23430940 DOI: 10.1007/8904_2011_117] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 11/09/2011] [Accepted: 11/10/2011] [Indexed: 02/03/2023] Open
Abstract
The mut-type methylmalonic aciduria (MMA, MIM 251000) is caused by a deficiency of mitochondrial methylmalonyl-CoA mutase (MCM, E.C. 5.4.99.2) activity, which results from defects in the MUT gene. To elucidate the mutation spectrum of the MUT gene in Chinese MMA patients, 13 exons of the MUT gene, including untranslated regions, were analyzed by PCR-based sequencing for 42 unrelated Chinese MMA patients. All the 42 patients were found to have at least one MUT mutation. A total of 41 mutations were identified. Of these mutations, 20 were novel ones, including one nonsense mutation (c.103C>T), 12 missense mutations (c.316A>C, c.424A>G, c.494A>G, c.554C>T, c.599T>C, c.919T>C, c.1009T>C, c.1061C>T, c.1141G>A, c.1208G>A, c.1267G>A, and c.1295A>C), one duplication (c.755dupA), three small deletions (c.398_399delGA, c.1046_1058del, and c.1835delG), two mutations that might affect mRNA splicing (c.754-1G>A and c.1084-10A>G), and one major deletion. Among the mutations identified, the c.1280G>A (15.5%), c.729_730insTT (10.7%), c.1106G>A (4.8%), c.1630_1631GG>TA (4.8%), and c.2080C>T (4.8%) accounted for 40% of the diseased alleles. The c.1280G>A and c.729_730insTT mutations were found to be the most frequent mutations in Southern and Northern Chinese, respectively. The results of microsatellite analysis suggest that the spread of c.729_730insTT among the Northern Chinese and of c.1280G>A and c.1630_1631GG>TA among the Southern Chinese may have undergone founder effects. This mutation analysis of the gene responsible for mut-type MMA will help to provide a molecular diagnostic aid for differential diagnosis of MMA and could be applied for carrier detection and prenatal diagnosis among Chinese family at risk of mut-type MMA.
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Chiu YH, Chang YC, Chang YH, Niu DM, Yang YL, Ye J, Jiang J, Okano Y, Lee DH, Pangkanon S, Kuptanon C, Hock NL, Chiong MA, Cavan BV, Hsiao KJ, Liu TT. Mutation spectrum of and founder effects affecting the PTS gene in East Asian populations. J Hum Genet 2012; 57:145-52. [DOI: 10.1038/jhg.2011.146] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Liu MY, Yang YL, Chang YC, Chiang SH, Lin SP, Han LS, Qi Y, Hsiao KJ, Liu TT. Mutation spectrum of MMACHC in Chinese patients with combined methylmalonic aciduria and homocystinuria. J Hum Genet 2010; 55:621-6. [PMID: 20631720 DOI: 10.1038/jhg.2010.81] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cblC type of combined methylmalonic aciduria (MMA) and homocystinuria (HC) is the most common inborn error of vitamin B(12) metabolism and is caused by mutations in the MMACHC gene. To elucidate the spectrum of mutations that causes combined MMA and HC in Chinese patients, the MMACHC gene was sequenced in 79 unrelated Chinese patients. Sequence analysis identified 98.1% of disease alleles and found that all patients had at least one MMACHC mutation. A total of 24 mutations were identified. Out of the 24 mutations identified, 9 were novel ones, including missense mutations (c.365A>T and c.452A>G), nonsense mutations (c.315C>G and c.615C>A), deletions (c.99delA and c.277-3_c.303del30), duplications (c.248dupT and c.626dupT) and an insertion (c.445_446insA). The c.609G>A, c.658_660delAAG, c.482G>A, c.394C>T and c.80A>G mutations were the most common mutations and accounted for 80% of disease alleles. Haplotype analysis suggests that the spread of the c.80A>G, c.609G>A and c.658_660delAAG mutations in Chinese patients were caused by a founder effect. The results indicate that defects occurring in the MMACHC gene are the major cause of this disease in Chinese patients with combined MMA and HC, and direct mutation analysis can therefore be used as a rapid confirmatory diagnosis among these Chinese patients.
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Affiliation(s)
- Mei-Ying Liu
- Institute of Genetics, National Yang-Ming University, Taipei, Taiwan
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12
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Vatanavicharn N, Kuptanon C, Liammongkolkul S, Liu TT, Hsiao KJ, Ratanarak P, Blau N, Wasant P. Novel mutation affecting the pterin-binding site of PTS gene and review of PTS mutations in Thai patients with 6-pyruvoyltetrahydropterin synthase deficiency. J Inherit Metab Dis 2009; 32 Suppl 1:S279-82. [PMID: 19830588 DOI: 10.1007/s10545-009-1221-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 07/30/2009] [Accepted: 08/25/2009] [Indexed: 10/20/2022]
Abstract
Tetrahydrobiopterin (BH(4)) deficiency comprises heterogeneous disorders resulting in hyperphenylalaninaemia (HPA) and lack of monoamine neurotransmitters. Among these, 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency is the most common disorder. We report a female Thai patient with PTPS deficiency who was initially detected by newborn screening for HPA, and later treated by supplements of BH(4), L-dopa/carbidopa, and 5-hydroxytryptophan. Monitoring of serum prolactin representing dopamine sufficiency is used for optimizing the dosage of L-dopa. She showed a remarkable progress of development despite delayed treatment at 5 months of age. Mutation analysis revealed two heterozygous missense mutations of the PTS gene: c.259C>T (p.P87S) inherited from the father; and c.147T>G (p.H49Q) inherited from the mother. The latter is a novel mutation that affects the pterin-binding site of the PTPS enzyme. This novel mutation expands the mutation spectrum of PTPS deficiency. Notably, some PTS mutations have been reported in both Thai and Chinese patients. Whether these common mutations are the result of a founder effect with common ancestors of Thai and Chinese people or intermarriage between Thai and Chinese descents in Thailand remain unclear. In conclusion, severe neurological impairment from BH(4) deficiency could be prevented by newborn screening for HPA and proper metabolic management. However, pterin analysis for early diagnosis of BH(4) deficiency is still not available in most developing countries.
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Affiliation(s)
- N Vatanavicharn
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, 2 Prannok Road, Bangkoknoi, Bangkok, Thailand.
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Thöny B, Blau N. Mutations in the BH4-metabolizing genes GTP cyclohydrolase I, 6-pyruvoyl-tetrahydropterin synthase, sepiapterin reductase, carbinolamine-4a-dehydratase, and dihydropteridine reductase. Hum Mutat 2006; 27:870-8. [PMID: 16917893 DOI: 10.1002/humu.20366] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Tetrahydrobiopterin (BH(4)) deficiencies are a highly heterogeneous group of disorders with several hundred patients, and so far a total of 193 different mutant alleles or molecular lesions identified in the GTP cyclohydrolase I (GTPCH), 6-pyruvoyl-tetrahydropterin synthase (PTPS), sepiapterin reductase (SR), carbinolamine-4a-dehydratase (PCD), or dihydropteridine reductase (DHPR) genes. The spectrum of mutations causing a reduction in one of the three biosynthetic (GTPCH, PTPS, and SR) or the two regenerating enzymes (PCD and DHPR) is tabulated and reviewed. Furthermore, current genomic variations or SNPs are also compiled. Mutations in GCH1 are scattered over the entire gene, and only 5 out of 104 mutant alleles, present in a homozygous state, are reported to cause the autosomal recessive form of inheritable hyperphenylalaninemia (HPA) associated with monoamine neurotransmitter deficiency. Almost all other 99 different mutant alleles in GCH1 are observed together with a wild-type allele and cause Dopa-responsive dystonia (DRD, Segawa disease) in a dominant fashion with reduced penetrance. Compound heterozygous or homozygous mutations are spread over the entire genes for PTS with 44 mutant alleles, for PCBD with nine mutant alleles, and for QDPR with 29 mutant alleles. These mutations cause an autosomal recessive inherited form of HPA, mostly accompanied by a deficiency of the neurotransmitters dopamine and serotonin. Lack of sepiapterin reductase activity, an autosomal recessive variant of BH(4) deficiency presenting without HPA, was diagnosed in patients with seven different mutant alleles in the SPR gene in exons 2 or 3 or in intron 2. Details on all mutations presented here are constantly updated in the BIOMDB database (www.bh4.org).
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Affiliation(s)
- Beat Thöny
- Division of Clinical Chemistry and Biochemistry, University Children's Hospital, Zurich, Switzerland
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Kim SW, Jang YJ, Chang JW, Hwang O. Degeneration of the nigrostriatal pathway and induction of motor deficit by tetrahydrobiopterin: an in vivo model relevant to Parkinson's disease. Neurobiol Dis 2003; 13:167-76. [PMID: 12828940 DOI: 10.1016/s0969-9961(03)00037-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
We determined whether the preferential toxicity of tetrahydrobiopterin (BH4) on dopamine-producing cells, which we have previously observed in vitro, might also occur in vivo and generate characteristics associated with Parkinson's disease. Intrastriatal BH4 injection caused a loss of tyrosine hydroxylase immunoreactivity and decreased dopamine content. The dopaminergic cell bodies topologically corresponding to the lesioned terminals were selectively degenerated. This was accompanied by a dose-dependent and asymmetric movement deficit in the contralateral forepaw. Direct injection of BH4 into the substantia nigra caused a loss of tyrosine hydroxylase immunoreactivity, but injection into the dorsal raphe was without effect on the GTP cyclohydrolase-immunoreactive serotonergic neurons, demonstrating selectivity for the dopaminergic system. BH4 exhibited a range of potency comparable to that of 6-hydroxydopamine. Thus, this animal model generated by the administration of BH4, the molecule endogenously present in the monoaminergic neurons, exhibited morphological, biochemical, and behavioral characteristics associated with Parkinson's disease and may be useful for studies in dopaminergic degeneration.
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Affiliation(s)
- Seong Who Kim
- Department of Biochemistry, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, South Korea
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Chien YH, Chiang SC, Huang A, Lin JM, Chiu YN, Chou SP, Chu SY, Wang TR, Hwu WL. Treatment and outcome of Taiwanese patients with 6-pyruvoyltetrahydropterin synthase gene mutations. J Inherit Metab Dis 2001; 24:815-23. [PMID: 11916314 DOI: 10.1023/a:1013984022994] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ten cases of tetrahydrobiopterin (BH4) deficiency were identified in 1,337,490 newborns screened in a Chinese population in Taiwan. The high incidence of BH4 deficiency in the Taiwanese population may be explained by a founder effect, since all of the patients revealed 6-pyruvoyltetrahydropterin synthase gene mutations, and grouping N52S and P87S mutations together constituted 88.9% of the disease alleles. BH4 supplementation with restriction of high-protein foods gave control of plasma phenylalanine within normal range, and levodopa itself prevented seizure. However, the average intelligence quotient (IQ) score of these patients was only 76 +/- 14 (56-98). Statistically, the age of starting medication, including 5-hydroxytryptophan (5-HTP), was inversely correlated to IQ scores of these patients. We suggest the combination of BH4, levodopa and 5-HTP as the standard protocol to commence the treatment of BH4 deficiency as early as possible, although prenatal brain damage could have existed.
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Affiliation(s)
- Y H Chien
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei
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Liu TT, Chiang SH, Wu SJ, Hsiao KJ. Tetrahydrobiopterin-deficient hyperphenylalaninemia in the Chinese. Clin Chim Acta 2001; 313:157-69. [PMID: 11694255 DOI: 10.1016/s0009-8981(01)00669-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Hyperphenylalaninemia (HPA) may be caused by either a deficiency in phenylalanine-4-hydroxylase or in tetrahydrobiopterin (BH4), the essential cofactor required for the hydroxylation of aromatic amino acids. The most common forms of BH4 deficiency are 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency (MIM 261640) and dihydropteridine reductase (DHPR) deficiency (MIM 261630), which require a different treatment from classical HPA. RESULTS Approximately 86% of BH4-deficient HPA in the Chinese population was found to be caused by PTPS deficiency. Eleven missense (73C-->G, 120T-->G, 155A-->G, 166G-->A, 200C-->T, 209T-->A, 226C-->T, 259C-->T, 286G-->A, 317C-->T, 430G-->C), one splicing (IVS3+1G-->A) and two deletion mutations (116-119delTGTT, 169-171delGTG) were identified in 37 unrelated PTPS-deficient Chinese families. Among these, 155A-->G, 259C-->T and 286G-->A mutation accounted for about 80% of the mutant alleles. The 155A-->G and 286G-->A mutations were found to be the common mutation in southern and northern Chinese, respectively. Only two Chinese DHPR-deficient families were detected among about 300 Chinese hyperphenylalaninemia cases. A single base transition 508G-->A on the DHPR cDNA was identified in two consanguineous DHPR-deficient siblings. A reduced level of DHPR mRNA expression was found in the other DHPR-deficient patient, which suggested that the mutation might lie in the regulatory region of the DHPR gene. CONCLUSIONS The BH4-deficient HPA was estimated to make up around 30% of the Chinese population in Taiwan suffering from HPA, which is much higher than in Caucasian populations (1.5-2% of HPA).
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Affiliation(s)
- T T Liu
- Institute of Genetics, National Yang-Ming University, Taipei, Taiwan, ROC
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Scherer-Oppliger T, Matasovic A, Laufs S, Levy HL, Quackenbush EJ, Blau N, Thöny B. Dominant negative allele (N47D) in a compound heterozygote for a variant of 6-pyruvoyltetrahydropterin synthase deficiency causing transient hyperphenylalaninemia. Hum Mutat 2000; 13:286-9. [PMID: 10220141 DOI: 10.1002/(sici)1098-1004(1999)13:4<286::aid-humu4>3.0.co;2-c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mutations in the 6-pyruvoyltetrahydropterin synthase (PTPS) gene result in persistent hyperphenylalaninemia and severe catecholamine and serotonin deficiencies. We investigated at the DNA level a family with a PTPS-deficient child presenting with an unusual form of transient hyperphenylalaninemia. The patient exhibited compound heterozygosity for the PTPS-mutant alleles N47D and D116G. Transfection studies with single PTPS alleles in COS-1 cells showed that the N47D allele was inactive, while D116G had around 66% of the wild-type activity. Upon co-transfection of two PTPS alleles into COS-1 cells, the N47D allele had a dominant negative effect on both the wild-type PTPS and the D116G mutant with relative reduction to about 20% of control values. Whereas the mother and the father had reduced enzyme activity in red blood cells (34.7% and 51.7%, respectively) and skin fibroblasts (2.8% and 15.4%, respectively), the clinically normal patient had in these cells activities at the detection limits, although PTPS-cross-reactive material was present in the fibroblasts. The specifically low PTPS activity in the mother's cells corroborated the evidence of a dominant negative effect of the maternal N47D allele on wild-type PTPS.
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Affiliation(s)
- T Scherer-Oppliger
- Division of Clinical Chemistry and Biochemistry, University Children's Hospital, Zurich, Switzerland
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Blau N, Scherer-Oppliger T, Baumer A, Riegel M, Matasovic A, Schinzel A, Jaeken J, Thöny B. Isolated central form of tetrahydrobiopterin deficiency associated with hemizygosity on chromosome 11q and a mutant allele of PTPS. Hum Mutat 2000; 16:54-60. [PMID: 10874306 DOI: 10.1002/1098-1004(200007)16:1<54::aid-humu10>3.0.co;2-c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
6-Pyruvoyl-tetrahydropterin synthase (PTS or PTPS) is involved in tetrahydrobiopterin (BH(4)) biosynthesis, the cofactor for various enzymes including the aromatic amino acid hydroxylases. Inherited PTPS deficiency is a heterogeneous disease with different phenotypes leading to BH(4) depletion. The severe form of PTPS deficiency causes hyperphenylalaninemia and monoamine neurotransmitter deficiency, whereas the mild form gives rise to hyperphenylalaninemia only. From 228 patients with PTPS deficiency at least 32 different mutant alleles have been identified on its corresponding gene, located on chromosome 11q22.3-q23.3. Here we describe a new allele from a child with PTPS deficiency who exhibited a mild but transient form of hyperphenylalaninemia, yet was deficient in CSF monoamines. The patient was found to carry, on her genomic DNA and cDNA, a homozygous A>G transition, leading to PTPS codon alteration Tyr99 to Cys (Y99C). The mother and several members of the maternal family were carriers of the Y99C allele, also verified by the reduced PTPS enzyme activity in erythrocytes. By cytogenetic, molecular, and FISH analyses, a de novo deletion spanning from 11q14 to 11q23.3 on the patient's paternal chromosome was mapped, establishing hemizygosity of the Y99C allele. The PTPS mutation observed in this patient generates a novel phenotype with an apparently isolated central form of BH(4) deficiency.
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Affiliation(s)
- N Blau
- Division of Clinical Chemistry and Biochemistry, University Children's Hospital, Zürich, Switzerland
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Single-Step Mutation Scanning of the 6-Pyruvoyltetrahydropterin Synthase Gene in Patients with Hyperphenylalaninemia. Clin Chem 1999. [DOI: 10.1093/clinchem/45.12.2102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AbstractBackground: Deficiency of 6-pyruvoyltetrahydropterin synthase (PTPS) is a recessively inherited disorder that leads to depletion of 5,6,7,8-tetrahydrobiopterin, the obligatory cofactor for hydroxylation of phenylalanine, tyrosine, and tryptophan. A marker for neonatal detection of PTPS deficiency is hyperphenylalaninemia (HPA). Molecular analysis would provide a simple and reliable means for distinguishing PTPS deficiency from other potential causes of HPA.Methods: We developed a method based on PCR in combination with denaturing gradient gel electrophoresis (DGGE) that rapidly scans the six coding sequences and all splice sites of the PTPS gene (PTS) for mutations. This method was used to examine the status of the PTS gene in control samples with known PTS mutations and in five patients with PTPS deficiency.Results: Two features of the PTS gene posed particular problems in relation to DGGE analysis: the very high GC content of exon 1, and a 15-bp poly(dT) stretch in the acceptor splice site of intron 1. Both problems were solved by special design of amplification primers. PCR and DGGE conditions were adjusted to allow simultaneous analysis of all six regions of the PTS gene. Using this one-step approach, all control mutations were readily resolved. Among the five PTPS patients, four mutations were identified, including IVS1-3C→G, IVS2-7T→A, V57del, and V97M (289G→A). The IVS1-3C→G mutation was shown by reverse transcription-PCR analysis to produce multiple splice variants.Conclusions: We have established a fast and reliable screening method for detection of mutations and small deletions/insertions in the PTS gene. This method should be useful for rapid diagnosis of PTPS deficiency in newborns with HPA.
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