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Zhu S, Hu Q, Yang Y, Zhu H, Wang J, Luo Z, Ou M, Chen A, Huang Y, Xiong F, Zhou J, Liu J, Lei X, Zeng L. Genotype characterization of tetrahydrobiopterin deficiency in two Tibetan children. Heliyon 2024; 10:e27050. [PMID: 38434370 PMCID: PMC10907759 DOI: 10.1016/j.heliyon.2024.e27050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 12/11/2023] [Accepted: 02/22/2024] [Indexed: 03/05/2024] Open
Abstract
Background Tetrahydrobiopterin (BH4) deficiency is a rare cause of hyperphenylalaninemia (HPA). The incidence of this condition varies based on region and ethnicity. In the early stages, patients typically do not exhibit any symptoms, and HPA is identified only through newborn screening for diseases. It is important to distinguish BH4 deficiency from phenylketonuria (PKU, MIM # 261600). Timely diagnosis and treatment of BH4 deficiency are crucial for the prognosis of patients. Case presentation We present two rare cases of Chinese Tibetan children with BH4D, diagnosed through biochemical tests and genetic sequencing. Case 1 is a male infant, 2 months old, with a newborn screening (NBS) Phe level of 1212 μmol/L (reference range <120 μmol). The biopterin(B) level was 0.19 mmol/molCr (reference range: 0.42-1.92 mmol/molCr), with a B% of 5.67% (reference range: 19.8%-50.3%). Gene sequencing revealed a homozygous missense variant [NM_000317.3 (PTS): c.259C > T (p.Pro87Ser), rs104894276, ClinVar variation ID: 480]. The patient was treated with a Phe-reduced diet and oral sapropterin, madopar and is currently 3 years and 4 months old, showing mild global developmental delay. Case 2 is a 40-day-old female infant with a Phe level of 2442.11 μmol/L and dihydropteridine reductase (DHPR) activity of 0.84 nmol/(min. 5 mm disc) (reference range: 1.02-3.35 nmol/min.5 mm disc. Gene sequencing revealed a compound heterozygous genotype [NM_000320.3(QDPR): c.68G > A (p.Gly23Asp), rs104893863, ClinVar Variation ID: 490] and [NM_000320.3(QDPR) c.419C > A (p. Ala140Asp), ClinVar ID: 2444501]. The patient was treated with a Phe-reduced diet and oral madopar, 5-hydroxytryptophan. At the age of 1 year, she exhibited severe global developmental delay with seizures. Conclusion We identified and treated two cases of BH4D in Tibetan populations in China, marking the first confirmed instances. Our report emphasizes the significance of conducting differential diagnosis tests for BH4D.
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Affiliation(s)
- Shuyao Zhu
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Qi Hu
- Department of Neonatal Screening Centre in Sichuan Province Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Yunxia Yang
- Department of Neonatal Screening Centre in Sichuan Province Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Hui Zhu
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Jin Wang
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, 610031, China
| | - Zemin Luo
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Mincai Ou
- Department of Neonatal Screening Centre in Sichuan Province Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Ai Chen
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Yu Huang
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Fu Xiong
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Jiaji Zhou
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Jinglin Liu
- Department of Neonatal Screening Centre in Sichuan Province Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Xunming Lei
- Department of Pediatrics, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, China
| | - Lan Zeng
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, Sichuan, 610031, China
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Nezhad SRK, Aligoodarzi PN, Rostami G, Shariati G, Galehdari H, Saberi A, Sedaghat A, Hamid M. Genotypic variants of the tetrahydrobiopterin (BH4) biosynthesis genes in patients with hyperphenylalaninemia from different regions of Iran. Mol Genet Genomic Med 2024; 12:e2294. [PMID: 37818795 PMCID: PMC10767420 DOI: 10.1002/mgg3.2294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 08/30/2023] [Accepted: 09/19/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Hyperphenylalaninemia (HPA) is a metabolic disorder classified into phenylalanine-4-hydroxylase (PAH) and non-PAH deficiency. The latter is produced by mutations in genes involved in the tetrahydrobiopterin (BH4) biosynthesis pathway and DNAJC12 pathogenetic variants. The BH4 metabolism, including de novo biosynthesis involved genes (i.e., guanosine 5'-triphosphate cyclohydrolase I (GTPCH/GCH1), sepiapterin reductase (SR/SPR), 6-pyruvoyl-tetrahydropterin synthase (PTPS/PTS)), and two genes that play roles in cofactor regeneration pathway (i.e., dihydropteridine reductase (DHPR/QDPR) and pterin-4α-carbinolamine dehydratase (PCD/PCBD1)). The subsequent systemic hyperphenylalaninemia and monoamine neurotransmitter deficiency lead to neurological consequences. The high rate of consanguineous marriages in Iran substantially increases the incidence of BH4 deficiency. METHODS We utilized the Sanger sequencing technique in this study to investigate 14 Iranian patients with non-PAH deficiency. All affected subjects in this study had HPA and no mutation was detected in their PAH gene. RESULTS We successfully identified six mutant alleles in BH4-deficiency-associated genes, including three novel mutations: one in QDPR, one in PTS, and one in the PCBD1 gene, thus giving a definite diagnosis to these patients. CONCLUSION In this light, appropriate patient management may follow. The clinical effect of reported variants is essential for genetic counseling and prenatal diagnosis in the patients' families and significant for the improvement of precision medicine.
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Affiliation(s)
| | | | - Golale Rostami
- Department of Molecular Medicine, Biotechnology Research CenterPasteur Institute of IranTehranIran
| | - Gholamreza Shariati
- Department of Medical Genetics, Faculty of MedicineAhvaz Jundishapur University of Medical SciencesAhvazIran
| | - Hamid Galehdari
- Department of Genetics, Faculty of SciencesShahid Chamran University of AhvazAhvazIran
| | - Alihossein Saberi
- Department of Medical Genetics, Faculty of MedicineAhvaz Jundishapur University of Medical SciencesAhvazIran
| | - Alireza Sedaghat
- Department of EndocrinologyAhvaz Jundishapur University of Medical SciencesAhvazIran
| | - Mohammad Hamid
- Department of Molecular Medicine, Biotechnology Research CenterPasteur Institute of IranTehranIran
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Vela-Amieva M, Alcántara-Ortigoza MA, Ibarra-González I, González-del Angel A, Fernández-Hernández L, Guillén-López S, López-Mejía L, Carrillo-Nieto RI, Fiesco-Roa MO, Fernández-Lainez C. Genotypic spectrum underlying tetrahydrobiopterin metabolism defects: Experience in a single Mexican reference center. Front Genet 2022; 13:993612. [PMID: 36313470 PMCID: PMC9597361 DOI: 10.3389/fgene.2022.993612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/30/2022] [Indexed: 11/29/2022] Open
Abstract
Background: Pterin profiles or molecular analyses of hyperphenylalaninemia (HPA) caused by phenylalanine hydroxylase (PAH) deficiency or tetrahydrobiopterin deficiency (BH4D) are not always available in low- or middle-income countries, including Mexico, limiting information regarding the phenotypic and genotypic characteristics of patients exhibiting BH4D. Objective: To report the genotypes underlying BH4D and the clinical presentation in unrelated Mexican HPA pediatric patients with normal PAH genotypes who attended a single metabolic reference center in Mexico. Methods: Automated Sanger sequencing of the PTS, QDPR, and PCBD1 genes of 14 HPA patients was performed. Predicted effects on protein structure caused by missense variants were assessed by in silico protein modeling. Results and discussion: A high prevalence of BH4D was noted in our HPA cohort (9.8%, N = 14/142). Clinically relevant biallelic genotypes were identified in the PTS (N = 7/14 patients), QDPR (N = 6/14 patients), and PCBD1 (N = 1/14 patients) genes. Four novel QDPR variants [c.714dup or p.(Leu239Thrfs*44), c.106-1G>T or p.(?), c.214G>T or p.(Gly72*), and c.187_189dup or p.(Gln63dup)] were identified. In silico protein modeling of six missense variants of PTS [p.(Thr67Met), p.(Glu81Ala), and p.(Tyr113Cys)], QDPR [p.(Cys161Phe) and p.(Pro172Leu)], and PCBD1 [p.(Glu97Lys)] supports their pathogenicity. Progressive neurological symptoms (mainly intellectual and motor impairment and even death in three patients) were noted in all patients with biallelic QDPR genotypes and in 5/7 patients bearing biallelic PTS genotypes. The single homozygous PCBD1 p.(Glu97Lys) patient remains asymptomatic. Conclusion: A higher proportion of BH4D (9.8 vs. 1%–2% worldwide), attributable to a heterogeneous mutational spectrum and wide clinical presentation, was noted in our Mexican HPA cohort, with the PTS-related HPA disorder being the most frequent. Sequencing-based assays could be a reliable approach for diagnosing BH4D in our population.
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Affiliation(s)
- M. Vela-Amieva
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
| | - M. A. Alcántara-Ortigoza
- Laboratorio de Biología Molecular, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
| | - I. Ibarra-González
- Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas, UNAM, Ciudad de México, México
| | - A. González-del Angel
- Laboratorio de Biología Molecular, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
| | - L. Fernández-Hernández
- Laboratorio de Biología Molecular, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
| | - S. Guillén-López
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
| | - L. López-Mejía
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
| | - R. I. Carrillo-Nieto
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
| | - M. O. Fiesco-Roa
- Laboratorio de Citogenética, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
- Maestría y Doctorado en Ciencias Médicas y de la Salud, UNAM, Ciudad de México, México
| | - C. Fernández-Lainez
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México, México
- *Correspondence: C. Fernández-Lainez,
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4
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The Utility of Genomic Testing for Hyperphenylalaninemia. J Clin Med 2022; 11:jcm11041061. [PMID: 35207333 PMCID: PMC8879487 DOI: 10.3390/jcm11041061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/08/2022] [Accepted: 02/16/2022] [Indexed: 12/10/2022] Open
Abstract
Hyperphenylalaninemia (HPA), the most common amino acid metabolism disorder, is caused by defects in enzymes involved in phenylalanine metabolism, with the consequent accumulation of phenylalanine and its secondary metabolites in body fluids and tissues. Clinical manifestations of HPA include mental retardation, and its early diagnosis with timely treatment can improve the prognosis of affected patients. Due to the genetic complexity and heterogeneity of HPA, high-throughput molecular technologies, such as next-generation sequencing (NGS), are becoming indispensable tools to fully characterize the etiology, helping clinicians to promptly identify the exact patients’ genotype and determine the appropriate treatment. In this review, after a brief overview of the key enzymes involved in phenylalanine metabolism, we represent the wide spectrum of genes and their variants associated with HPA and discuss the utility of genomic testing for improved diagnosis and clinical management of HPA.
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5
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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: 26] [Impact Index Per Article: 8.7] [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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6
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Bozaci AE, Er E, Yazici H, Canda E, Kalkan Uçar S, Güvenc Saka M, Eraslan C, Onay H, Habif S, Thöny B, Coker M. Tetrahydrobiopterin deficiencies: Lesson from clinical experience. JIMD Rep 2021; 59:42-51. [PMID: 33977029 PMCID: PMC8100404 DOI: 10.1002/jmd2.12199] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVES The present study describes clinical, biochemical, molecular genetic data, current treatment strategies and follow-up in nine patients with tetrahydrobiopterin (BH4) deficiency due to various inherited genetic defects. METHODS We analyzed clinical, biochemical, and molecular data of nine patients with suspected BH4 deficiency. All patients were diagnosed at Ege University Faculty of Medicine in Izmir, Turkey and comprised data collected from 2006 to 2019. The diagnostic laboratory examinations included blood phenylalanine and urinary or plasma pterins, dihydropteridine reductase (DHPR) enzyme activity measurement in dried blood spots, folic acid and monoamine neurotransmitter metabolites in cerebrospinal fluid, as well as DNA sequencing. RESULTS Among the nine patients, we identified one with autosomal recessive GTP cyclohydrolase I (ar GTPCH) deficiency, two with 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency, three with sepiapterin reductase (SR) deficiency, and three with DHPR deficiency. Similar to previous observations, the most common clinical symptoms are developmental delay, intellectual disability, and movement disorders. All patients received treatment with l-dopa and 5-hydroxytryptophan, while only the ar GTPCH, the PTPS, and one DHPR deficient patients were supplemented in addition with BH4. The recommended dose range varies among patients and depends on the type of disease. The consequences of BH4 deficiencies are quite variable; however, early diagnosis and treatment will improve outcomes. CONCLUSIONS As BH4 deficiencies are rare group of treatable neurometabolic disorders, it is essential to diagnose the underlying (genetic) defect in newborns with hyperphenylalaninemia. Irreversible brain damage and progressive neurological deterioration may occur in untreated or late diagnosed patients. Prognosis could be satisfying in the cases with early diagnose and treatment.
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Affiliation(s)
- Ayse Ergul Bozaci
- Department of Pediatrics, Division of Pediatric MetabolismEge University Faculty of MedicineIzmirTurkey
| | - Esra Er
- Tepecik Research and Training Hospital, Department of GeneticsIzmirTurkey
| | - Havva Yazici
- Department of Pediatrics, Division of Pediatric MetabolismEge University Faculty of MedicineIzmirTurkey
| | - Ebru Canda
- Department of Pediatrics, Division of Pediatric MetabolismEge University Faculty of MedicineIzmirTurkey
| | - Sema Kalkan Uçar
- Department of Pediatrics, Division of Pediatric MetabolismEge University Faculty of MedicineIzmirTurkey
| | - Merve Güvenc Saka
- Tepecik Research and Training Hospital, Department of GeneticsIzmirTurkey
| | - Cenk Eraslan
- Department of RadiologyEge University Faculty of MedicineIzmirTurkey
| | - Hüseyin Onay
- Department of Medical GeneticsEge University Faculty of MedicineIzmirTurkey
| | - Sara Habif
- Department of Medical BiochemistryEge University Faculty of MedicineIzmirTurkey
| | - Beat Thöny
- Division of MetabolismUniversity Children's Hospital Zurich and Children's Research CenterZurichSwitzerland
| | - Mahmut Coker
- Department of Pediatrics, Division of Pediatric MetabolismEge University Faculty of MedicineIzmirTurkey
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7
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Li N, Yu P, Rao B, Deng Y, Guo Y, Huang Y, Ding L, Zhu J, Yang H, Wang J, Guo J, Chen F, Liu Z. Molecular genetics of tetrahydrobiopterin deficiency in Chinese patients. J Pediatr Endocrinol Metab 2018; 31:911-916. [PMID: 30001213 DOI: 10.1515/jpem-2018-0037] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 05/14/2018] [Indexed: 11/15/2022]
Abstract
Background The overall incidence of hyperphenylalaninemia (HPA) in China is 1:11,763, with tetrahydrobiopterin (BH4) deficiency accounting for 8.55% of patients with HPA in the mainland. Much progress has been made in the diagnosis and treatment of BH4 deficiency with the introduction of neonatal screening in China. However, the screening rate is still low and screening is not universally available. Methods A total of 44 BH4-deficient patients were enrolled in this study, of which 39 were diagnosed with BH4 deficiency, while the remaining five showed typical characteristics of BH4 deficiency at a later period. The entire coding regions and adjacent intronic regions of GCH1, PTS, PCBD1 and QDPR genes were analyzed using target sequencing. Results Nineteen (n=19) different mutations in the PTS gene including four novel mutations and one mutation in QDPR were identified. p.P87S, p.D96N, IVS1-291A>G, p.N52S, p.K91R, p.V56M, p.T106M and p.F40GfsX53 in PTS were the prevalent mutations with ≥3% relative frequency. The mutation p.R221X in the QDPR gene was found with relatively lower frequencies (2.27%). The remaining 12 mutations in PTS were found at relative frequencies of 1.14%. Conclusions The results could be of value for genetic counseling and prenatal diagnosis in the patients' families and for the molecular diagnosis of BH4 deficiencies. Furthermore, four novel mutations expand and improve the PTS mutation database.
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Affiliation(s)
- Nana Li
- National Center for Birth Defects Monitoring, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, Sichuan, P.R. China
| | - Ping Yu
- National Center for Birth Defects Monitoring, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, Sichuan, P.R. China
| | - Bin Rao
- BGI-Shenzhen, Shenzhen, P.R. China.,China National GeneBank, BGI-Shenzhen, Shenzhen, P.R. China
| | - Ying Deng
- National Center for Birth Defects Monitoring, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, P.R. China
| | - Yixiong Guo
- National Center for Birth Defects Monitoring, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, P.R. China
| | - Yushan Huang
- BGI-Shenzhen, Shenzhen, P.R. China.,China National GeneBank, BGI-Shenzhen, Shenzhen, P.R. China
| | - Lijie Ding
- BGI-Shenzhen, Shenzhen, P.R. China.,China National GeneBank, BGI-Shenzhen, Shenzhen, P.R. China
| | - Jun Zhu
- National Center for Birth Defects Monitoring, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, P.R. China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, Sichuan, P.R. China
| | - Huanming Yang
- BGI-Shenzhen, Shenzhen, P.R. China.,James D. Watson Institute of Genome Sciences, Hangzhou, P.R. China
| | - Jian Wang
- BGI-Shenzhen, Shenzhen, P.R. China.,James D. Watson Institute of Genome Sciences, Hangzhou, P.R. China
| | - Jian Guo
- BGI-Shenzhen, Building 11, Beishan Industrial Zone, Yantian, Shenzhen, Guangdong, P.R. China, Phone: 86-15914038192.,BGI-Shenzhen, Building 11, Beishan Industrial Zone, Yantian, Shenzhen, Guangdong, P.R. China, Phone: 86-13428735579.,China National GeneBank, BGI-Shenzhen, Shenzhen, Guangdong, P.R. China
| | - Fang Chen
- BGI-Shenzhen, Building 11, Beishan Industrial Zone, Yantian, Shenzhen, Guangdong, P.R. China, Phone: 86-15914038192.,BGI-Shenzhen, Building 11, Beishan Industrial Zone, Yantian, Shenzhen, Guangdong, P.R. China, Phone: 86-13428735579.,China National GeneBank, BGI-Shenzhen, Shenzhen, Guangdong, P.R. China
| | - Zhen Liu
- National Center for Birth Defects Monitoring, West China Second University Hospital, Sichuan University, 20, Section 3, Ren Min South Road, Chengdu, Sichuan, P.R. China, Phone: 86-028-85502490, Fax: 86-028-85501386.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, P.R. China
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8
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Deng H, Zheng W, Jankovic J. Genetics and molecular biology of brain calcification. Ageing Res Rev 2015; 22:20-38. [PMID: 25906927 DOI: 10.1016/j.arr.2015.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 01/01/2023]
Abstract
Brain calcification is a common neuroimaging finding in patients with neurological, metabolic, or developmental disorders, mitochondrial diseases, infectious diseases, traumatic or toxic history, as well as in otherwise normal older people. Patients with brain calcification may exhibit movement disorders, seizures, cognitive impairment, and a variety of other neurologic and psychiatric symptoms. Brain calcification may also present as a single, isolated neuroimaging finding. When no specific cause is evident, a genetic etiology should be considered. The aim of the review is to highlight clinical disorders associated with brain calcification and provide summary of current knowledge of diagnosis, genetics, and pathogenesis of brain calcification.
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Affiliation(s)
- Hao Deng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha, China; Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China.
| | - Wen Zheng
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha, China; Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China
| | - Joseph Jankovic
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
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9
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Foroozani H, Abiri M, Salehpour S, Bagherian H, Sharifi Z, Alaei MR, Khatami S, Azadmeh S, Setoodeh A, Rejali L, Rohani F, Zeinali S. Molecular Characterization of QDPR Gene in Iranian Families with BH4 Deficiency: Reporting Novel and Recurrent Mutations. JIMD Rep 2015; 21:123-8. [PMID: 26006720 DOI: 10.1007/8904_2015_441] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 04/08/2015] [Accepted: 04/10/2015] [Indexed: 04/03/2023] Open
Abstract
Newborn screening for PKU has been in practice in Iran since 2007. Some hyperphenylalaninemia cases have tetrahydrobiopterin (BH4) biosynthesis deficiency/disorder. Several genes including QDPR (encodes DHPR enzyme, the necessary cofactor for PAH activity) have been associated with the BH4. Mutations have been previously described in the QDPR gene. The incidence of BH4 deficiency is expected to be higher in Iran due to high rate of consanguineous marriages.We identified a total of 93 BH4-deficient families. A multiplex set of STR markers linked to 4 genes responsible for the BH4 deficiency (i.e., GCH1, PCBD1, PTS, and QDPR genes) was used to quickly determine which gene may be responsible to cause the disease. Mutation analysis of QDPR gene revealed some known and novel mutations. Our findings show that no common mutation predominates, and they are scattered in the gene in our population.
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Affiliation(s)
- Hannaneh Foroozani
- Department of Biology, Pharmaceutical Science Branch, Islamic Azad University, Tehran, Iran
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10
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Lu DY, Ye J, Han LS, Qiu WJ, Zhang HW, Zhou JD, Bao PZ, Zhang YF, Gu XF. QDPR gene mutation and clinical follow-up in Chinese patients with dihydropteridine reductase deficiency. World J Pediatr 2014; 10:219-26. [PMID: 25124972 DOI: 10.1007/s12519-014-0496-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 01/10/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND This study aimed to investigate the mutation spectrum of the QDPR gene, to determine the effect of mutations on dihydropteridine reductase (DHPR) structure/function, to discuss the potential genotypephenotype correlation, and to evaluate the clinical outcome of Chinese patients after treatment. METHODS Nine DHPR-deficient patients were enrolled in this study and seven of them underwent neonatal screening. QDPR gene mutations were analyzed and confirmed by routine methods. The potential pathogenicity of missense variants was analyzed using Clustal X, PolyPhen program and Swiss-PDB Viewer 4.04_OSX software, respectively. The clinical outcomes of the patients were evaluated after long-term treatment. RESULTS In 10 mutations of the 9 patients, 4 were novel mutations (G20V, V86D, G130S and A175R), 4 were reported by us previously, and 2 known mutations were identified. R221X was a hotspot mutation (27.7%) in our patients. Eight missense mutations probably had damage to protein. Six patients in this series were treated with a good control of phenylalanine level. The height and weight of the patients were normal at the age of 4 months to 7.5 years. Four patients, who underwent a neonatal screening and were treated early, showed a normal mental development. In 2 patients diagnosed late, neurological symptoms were significantly improved. CONCLUSIONS The mutation spectrum of the QDPR gene is different in the Chinese population. Most mutations are related to severe phenotype. The determination of DHPR activity should be performed in patients with hyperphenylalaninemia. DHPR-deficient patients who were treated below the age of 2 months may have a near normal mental development.
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Affiliation(s)
- De-Yun Lu
- Department of Pediatric Endocrinology and Genetic Metabolism and Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200092, China
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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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Abstract
Brain calcinosis syndrome (BCS) usually is defined as bilateral calcium accumulation in the brain parenchyma, primarily in the basal ganglia. More than 50 reported clinical conditions have been associated with BCS. We reviewed clinical, radiological, and genetic features of heredofamilial BCS accompanying all conditions associated with calcium accumulation in the brain reported in English between 1962 and 2003 in MEDLINE. The location, extent, and degree of calcification in the brain show diversity not only among the various disorders but also among patients sharing the same condition. The pathogenesis of BCS is uncertain. More complicated mechanisms may be Involved when brain calcinosis is present but calcium, phosphorus, and parathyroid hormone metabolism abnormalities are absent. We review conditions associated with heredofamilial BCS in which brain calcinosis is nearly uniformly present because such information may be Important to the clinician pursuing an investigative strategy.
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Affiliation(s)
- Yasuhiko Baba
- Department of Neurology, Mayo Clinic College of Medicine, Jacksonville, Fla 32224, USA
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Ponzone A, Spada M, Ferraris S, Dianzani I, de Sanctis L. Dihydropteridine reductase deficiency in man: from biology to treatment. Med Res Rev 2004; 24:127-50. [PMID: 14705166 DOI: 10.1002/med.10055] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In 1975, dihydropteridine reductase (DHPR) deficiency was first recognized as a cause of tetrahydrobiopterin (BH(4)) deficiency, leading to hyperphenylalaninemia (HPA) and impaired biogenic amine deficiency. So far, more than 150 patients scattered worldwide have been reported and major progresses have been made in the understanding of physiopathology, screening, diagnosis, treatment, and molecular genetics of this inherited disease. Present knowledge on different aspects of DHPR deficiency, largely derived from authors' personal experience, is traced in this article.
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Kalkanoglu HS, Romstad A, Coşkun T, Güttler F. Evaluation of a fetus at risk for dihydropteridine reductase deficiency by direct mutation analysis using denaturing gradient gel electrophoresis. Prenat Diagn 2001; 21:868-70. [PMID: 11746132 DOI: 10.1002/pd.161] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dihydropteridine reductase (DHPR) is an enzyme involved in the recycling of tetrahydrobiopterin (BH(4)), which is an obligate co-factor of the aromatic amino acid hydroxylases. DHPR deficiency is a rare, autosomal recessive disorder caused by mutations in the QDPR gene. DHPR-deficient patients are diagnosed by a lack of response to a low phenylalanine diet and by severe neurological symptoms. Final diagnosis is made by measurements of neurotransmitters and pterin metabolites in cerebrospinal fluid (CSF) and urine, in addition to DHPR enzyme activity, which can be assessed in whole red blood cells. Treatment of DHPR deficiency can be difficult and the outcome is not always satisfying, even if all treatment strategies are followed. Therefore prenatal diagnosis is of great importance in affected families. Prenatal diagnosis is possible by measuring DHPR activity in different cell types but this is time consuming. More than 25 different mutations have to date been identified in the QDPR gene and direct identification of a mutation in a fetus would be easy and rapid. We have developed a method based on denaturing gradient gel electrophoresis (DGGE) for the analysis of the QDPR gene. The method is useful for rapid and simultaneous scanning of all exons and flanking intronic sequences of the QDPR gene. We describe the first prenatal diagnosis conducted using this method.
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Affiliation(s)
- H S Kalkanoglu
- Hacettepe University, Department of Pediatrics, Division of Nutrition and Metabolism, TR-06100 Ankara, Turkey.
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