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Shang Z, Xie P, Pan K, Liu J, Xu W, Hu Y, Tang L, Leng Q, Liu S, He C. Predictive value of fluorometric method and tandem mass spectrometry for hyperphenylalaninemia and its subtypes in China: A systematic review and meta‑analysis. Exp Ther Med 2024; 28:278. [PMID: 38800050 PMCID: PMC11117103 DOI: 10.3892/etm.2024.12566] [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: 10/15/2023] [Accepted: 04/04/2024] [Indexed: 05/29/2024] Open
Abstract
The present study aimed to conduct a comprehensive meta-analysis to assess the diagnostic value of fluorometric assays and tandem mass spectrometry (MS/MS) for hyperphenylalaninemia (HPA) and its subtypes. The PubMed, Embase and Cochrane Library databases were searched from inception to October 2023. The present study included studies that reported the newborn screening and genetic features of patients with HPA and excluded duplicate publications, studies without full text, studies with incomplete information, studies from which it was not possible to extract data, animal experiments, reviews and systematic reviews. STATA 15.1 was used to analyze the data. The pooled results revealed that 0.04% [95% confidence interval (CI): 0.019-0.069] of neonatal HPA fluorometric assays and MS/MS. The positive predictive value (PPV) of neonatal HPA screening using fluorometric assays and tandem mass spectrometry was 31.7% (95% CI: 19.6-45.2). Notably, the PPV of neonatal HPA screening using fluorometric assays was 8.3% (95% CI: 7.1-9.6), while the PPV of neonatal HPA screening using tandem mass spectrometry was 31.8% (95% CI: 16.4-49.4). Additionally, the pooled results showed that the incidence of tetrahydrobiopterin deficiency (BH4D) in HPA patients was 12.43% (95% CI: 3.28-25.75) and the incidence of phenylalanine hydroxylase deficiency (PAHD) in HPA patients was 88.65% (95% CI: 78.84-95.86). Newborn screening is an effective method for the early detection of HPA and MS/MS has a greater PPA than fluorometric assays for diagnosing HPA. In addition, in the screening of HPA, the proportion of HPA patients with PAHD was significantly higher than that of patients with BH4D.
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Affiliation(s)
- Zhirong Shang
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Pan Xie
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Ke Pan
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Jialin Liu
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Wei Xu
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Yue Hu
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Li Tang
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Qinghua Leng
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Shuyu Liu
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
| | - Chengchuan He
- Department of Clinical Laboratory, Mianyang Maternity and Child Healthcare Hospital, Mianyang, Sichuan 621000, P.R. China
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Su H, Zhang H, Wu J, Huang L, Zhang M, Xu W, Cao J, Liu W, Liu N, Jiang H, Gu X, Qian K. Fast Label-Free Metabolic Profile Recognition Identifies Phenylketonuria and Subtypes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305701. [PMID: 38348590 PMCID: PMC11022714 DOI: 10.1002/advs.202305701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/25/2024] [Indexed: 04/18/2024]
Abstract
Phenylketonuria (PKU) is the most common inherited metabolic disease in humans. Clinical screening of newborn heel blood samples for PKU is costly and time-consuming because it requires multiple procedures, like isotope labeling and derivatization, and PKU subtype identification requires an additional urine sample. Delayed diagnosis of PKU, or subtype identification can result in mental disability. Here, plasmonic silver nanoshells are used for laser desorption/ionization mass spectrometry (MS) detection of PKU with label-free assay by recognizing metabolic profile in dried blood spot (DBS) samples. A total of 1100 subjects are recruited and each DBS sample can be processed in seconds. This platform achieves PKU screening with a sensitivity of 0.985 and specificity of 0.995, which is comparable to existing clinical liquid chromatography MS (LC-MS) methods. This method can process 360 samples per hour, compared with the LC-MS method which processes only 30 samples per hour. Moreover, this assay enables precise identification of PKU subtypes without the need for a urine sample. It is demonstrated that this platform enables high-performance and fast, low-cost PKU screening and subtype identification. This approach might be suitable for the detection of other clinically relevant biomarkers in blood or other clinical samples.
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Affiliation(s)
- Haiyang Su
- Henan Key Laboratory of Rare DiseasesEndocrinology and Metabolism CenterThe First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and TechnologyLuoyang471003P. R. China
- State Key Laboratory of Systems Medicine for CancerSchool of Biomedical EngineeringInstitute of Medical Robotics and Shanghai Academy of Experimental MedicineShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Huiwen Zhang
- Xinhua HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200092P. R. China
| | - Jiao Wu
- State Key Laboratory of Systems Medicine for CancerSchool of Biomedical EngineeringInstitute of Medical Robotics and Shanghai Academy of Experimental MedicineShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Lin Huang
- Country Department of Clinical Laboratory MedicineShanghai Chest HospitalShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Mengji Zhang
- State Key Laboratory of Systems Medicine for CancerSchool of Biomedical EngineeringInstitute of Medical Robotics and Shanghai Academy of Experimental MedicineShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Wei Xu
- State Key Laboratory for Oncogenes and Related GenesDivision of CardiologyRenji Hospital, School of Medicine, Shanghai Jiao Tong UniversityShanghai200127P. R. China
| | - Jing Cao
- State Key Laboratory of Systems Medicine for CancerSchool of Biomedical EngineeringInstitute of Medical Robotics and Shanghai Academy of Experimental MedicineShanghai Jiao Tong UniversityShanghai200030P. R. China
| | - Wanshan Liu
- Xinhua HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200092P. R. China
| | - Ning Liu
- School of Electronics Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai200240P. R. China
| | - Hongwei Jiang
- Henan Key Laboratory of Rare DiseasesEndocrinology and Metabolism CenterThe First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and TechnologyLuoyang471003P. R. China
| | - Xuefan Gu
- Xinhua HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200092P. R. China
| | - Kun Qian
- State Key Laboratory of Systems Medicine for CancerSchool of Biomedical EngineeringInstitute of Medical Robotics and Shanghai Academy of Experimental MedicineShanghai Jiao Tong UniversityShanghai200030P. R. China
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Qiu X, Zhao P, Luo J, Li G, Deng L, Zeng Y, Xu L, Zhou J. Biochemical and molecular features of tetrahydrobiopterin deficiency in Fujian Province, southeastern China. Front Genet 2023; 14:1250568. [PMID: 37636258 PMCID: PMC10451069 DOI: 10.3389/fgene.2023.1250568] [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: 06/30/2023] [Accepted: 08/04/2023] [Indexed: 08/29/2023] Open
Abstract
The estimated prevalence of tetrahydrobiopterin deficiency (BH4D) and the mutational spectrum of the causal 6-pyruvoyl-tetrahydropterin synthase (PTS) gene vary widely according to race and region. This study assessed the prevalence and genetic characteristics of BH4D in Fujian Province, southeastern China. A total of 3,204,067 newborns were screened between 2012 and 2022 based on the phenylalanine level and the phenylalanine/tyrosine ratio in dried blood spots. Differential diagnosis was determined by the urine purine spectrum, dihydropteridine reductase activity in red blood cells, and genetic testing. The PTS mutation spectrum and genotypes were determined by next-generation sequencing. A total of 189 newborns were diagnosed with hyperphenylalaninemia (HPA) over the study period, including 159 with phenylalanine hydroxylase deficiency and 30 with BH4D. Therefore, the prevalence of BH4D in Fujian was 9.36 per 1,000,000 live births (30/3,204,067) and the proportion of BH4D among patients with HPA was 15.87% (30/189). A total of 58 PTS alleles were identified in the 29 patients with PTS deficiency (PTPSD), and those alleles were composed of 10 different variants, including eight missense variants and two splice-site variants. The most prevalent variants were c.155A>G, p.Asn52Ser (44.83%); c.259C>T, p.Pro87Ser (39.66%); and c.84-291A>G, p.Tyr27Argfs*8 (3.45%). The predominant genotype was c [155A>G]; [259C>T] (11/29, 37.93%). The prevalence of BH4D and the spectrum of associated PTS mutations were successfully determined for the first time in Fujian Province, southeastern China. Since the mutation spectrum of PTS is region-specific, such data will facilitate molecular diagnosis and genetic counseling in PTPSD cases.
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Affiliation(s)
- Xiaolong Qiu
- Genetic Diagnosis and Therapy Center, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
| | - Peiran Zhao
- Genetic Diagnosis and Therapy Center, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
| | - Jinying Luo
- Obstetrics and Gynecology Department, Fujian Maternity and Child Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
| | - Guilin Li
- Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, China
| | - Lin Deng
- Obstetrics and Gynecology Department, Fujian Maternity and Child Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
| | - Yinglin Zeng
- Genetic Diagnosis and Therapy Center, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
| | - Liangpu Xu
- Genetic Diagnosis and Therapy Center, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
| | - Jinfu Zhou
- Genetic Diagnosis and Therapy Center, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
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Chen T, Lu D, Xu F, Ji W, Zhan X, Gao X, Qiu W, Zhang H, Liang L, Gu X, Han L. Newborn screening of maple syrup urine disease and the effect of early diagnosis. Clin Chim Acta 2023; 548:117483. [PMID: 37421976 DOI: 10.1016/j.cca.2023.117483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 07/03/2023] [Accepted: 07/05/2023] [Indexed: 07/10/2023]
Abstract
BACKGROUND Maple syrup urine disease (MSUD) is a rare disease for which newborn screening (NBS) is feasible but not universally applied in China. We shared our experiences with MSUD NBS. METHODS Tandem mass spectrometry-based NBS for MSUD was implemented in January 2003, and diagnostic methods included urine organic acid analysis via gas chromatography-mass spectrometry and genetic analysis. RESULTS Six MSUD patients were identified from 1.3 million newborns, yielding an incidence of 1:219,472, in Shanghai, China. The areas under the curve (AUCs) of total leucine (Xle), Xle/phenylalanine ratio, and Xle/alanine ratio were all 1.000. Some amino acid and acylcarnitine concentrations were markedly low in MSUD patients. 47 MSUD patients identified here and in other centers were investigated, which included 14 patients identified by NBS and 33 patients diagnosed clinically. Forty-four patients were subclassified into classic (n = 29), intermediate (n = 11) and intermittent (n = 4) subtypes. Due to earlier diagnosis and treatment, screened classic patients showed a higher survival rate (62.5%, 5/8) than clinically diagnosed classic patients (5.2%, 1/19). Overall, 56.8% (25/44) of MSUD patients and 77.8% (21/27) of classic patients carried variants in the BCKDHB gene. Among 61 identified genetic variants, 16 novel variants were identified. CONCLUSION MSUD NBS in Shanghai, China, enabled earlier detection and increased survivorship in the screened population.
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Affiliation(s)
- Ting Chen
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Deyun Lu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Feng Xu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Wenjun Ji
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Xia Zhan
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Xiaolan Gao
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Wenjuan Qiu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Huiwen Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Lili Liang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Xuefan Gu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Lianshu Han
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
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5
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Zhang C, Yan Y, Zhou B, Wang Y, Tian X, Hao S, Ma P, Zheng L, Zhang Q, Hui L, Wang Y, Cao Z, Ma X. Identification of deep intronic variants of PAH in phenylketonuria using full-length gene sequencing. Orphanet J Rare Dis 2023; 18:128. [PMID: 37237386 PMCID: PMC10214626 DOI: 10.1186/s13023-023-02742-1] [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: 01/04/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND Phenylketonuria (PKU) is an autosomal recessive congenital metabolic disorder caused by PAH variants. Previously, approximately 5% of PKU patients remained undiagnosed after Sanger sequencing and multiplex ligation-dependent probe amplification. To date, increasing numbers of pathogenic deep intronic variants have been reported in more than 100 disease-associated genes. METHODS In this study, we performed full-length sequencing of PAH to investigate the deep intronic variants in PAH of PKU patients without definite genetic diagnosis. RESULTS We identified five deep intronic variants (c.1199+502A>T, c.1065+241C>A, c.706+368T>C, c.706+531>C, and c.706+608A>C). Of these, the c.1199+502A>T variant was found at high frequency and may be a hotspot PAH variant in Chinese PKU. c.706+531T>C and c.706+608A>C are two novel variants that extend the deep intronic variant spectrum of PAH. CONCLUSION Deep intronic variant pathogenicity analysis can further improve the genetic diagnosis of PKU patients. In silico prediction and minigene analysis are powerful approaches for studying the functions and effects of deep intronic variants. Targeted sequencing after full-length gene amplification is an economical and effective tool for the detection of deep intron variation in genes with small fragments.
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Affiliation(s)
- Chuan Zhang
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
- National Research Institute for Health and Family Planning, National Human Genetic Resources Center, Beijing, China
- Graduate School of Peking, Union Medical College, Beijing, China
| | - Yousheng Yan
- Prenatal Diagnostic Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University; Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Bingbo Zhou
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Yupei Wang
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Xinyuan Tian
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Shengju Hao
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Panpan Ma
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Lei Zheng
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Qinghua Zhang
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Ling Hui
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Yan Wang
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Zongfu Cao
- National Research Institute for Health and Family Planning, National Human Genetic Resources Center, Beijing, China.
| | - Xu Ma
- National Research Institute for Health and Family Planning, National Human Genetic Resources Center, Beijing, China.
- Graduate School of Peking, Union Medical College, Beijing, China.
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6
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Zhang C, Zhang P, Yan Y, Zhou B, Wang Y, Tian X, Hao S, Ma P, Zheng L, Zhang Q, Hui L, Wang Y, Cao Z, Ma X. The spectrum of phenylalanine hydroxylase variants and genotype-phenotype correlation in phenylketonuria patients in Gansu, China. Hum Genomics 2023; 17:36. [PMID: 37098607 PMCID: PMC10127316 DOI: 10.1186/s40246-023-00475-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/15/2023] [Indexed: 04/27/2023] Open
Abstract
BACKGROUND Phenylketonuria (PKU) is a common, congenital, autosomal recessive, metabolic disorder caused by Phenylalanine hydroxylase (PAH) variants. METHODS 967 PKU patients from Gansu, China were genotyped by Sanger sequencing, multiplex ligation-dependent probe amplification, and whole exome sequencing. We analyzed the variants of PAH exons, their flanking sequences, and introns. RESULTS The detection of deep intronic variants in PAH gene can significantly improve the genetic diagnostic rate of PKU. The distribution of PAH variants among PKU subtypes may be related to the unique genetic background in Gansu, China. CONCLUSION The identification of PAH hotspot variants will aid the development of large-scale neonatal genetic screening for PKU. The five new PAH variants found in this study further expand the spectrum of PAH variants. Genotype-phenotype correlation analysis may help predict the prognosis of PKU patients and enable precise treatment regimens to be developed.
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Affiliation(s)
- Chuan Zhang
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
- National Research Institute for Family Planning , National Human Genetic Resources Center, Beijing, China
| | - Pei Zhang
- Department of Nosocomial Infection Management, Lanzhou University Second Hospital, Lanzhou, China
| | - Yousheng Yan
- Prenatal Diagnostic Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Bingbo Zhou
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Yupei Wang
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Xinyuan Tian
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Shengju Hao
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Panpan Ma
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Lei Zheng
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Qinghua Zhang
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Ling Hui
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Yan Wang
- Gansu Province Medical Genetics Center,Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Zongfu Cao
- National Research Institute for Family Planning , National Human Genetic Resources Center, Beijing, China.
| | - Xu Ma
- National Research Institute for Family Planning , National Human Genetic Resources Center, Beijing, China.
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Luo X, Wang R, Sun Y, Qiu W, Lu D, Wang Y, Gong Z, Zhang H, Han L, Liang L, Gu X, Yu Y, Xiao B. Deep Intronic PAH Variants Explain Missing Heritability in Hyperphenylalaninemia. J Mol Diagn 2023; 25:284-294. [PMID: 36849017 DOI: 10.1016/j.jmoldx.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/18/2023] [Accepted: 02/02/2023] [Indexed: 02/27/2023] Open
Abstract
Phenylalanine hydroxylase (PAH) deficiency or phenylketonuria (PKU) is the most common cause of hyperphenylalaninemia (HPA), and approximately 5% of patients remain genetically unsolved. Identifying deep intronic PAH variants may help improve their molecular diagnostic rate. Next-generation sequencing was utilized to detect the whole PAH gene in 96 patients with genetically unsolved HPA from 2013 to 2022. The effects of deep intronic variants on pre-mRNA splicing were investigated by minigene-based assay. The allelic phenotype values of recurrent deep intronic variants were calculated. Twelve deep intronic PAH variants, located in intron 5 (c.509+434C>T), intron 6 (c.706+288T>G, c.706+519T>C, c.706+531T>C, c.706+535G>T, c.706+600A>C, c.706+603T>G, and c.706+608A>C), intron 10 (c.1065+241C>A and c.1065+258C>A), and intron 11 (c.1199+502A>T and c.1199+745T>A) were identified in 80.2% (77/96) patients. Ten of the 12 variants were novel, and they all generated pseudoexons in mRNA, leading to frameshift or lengthened proteins. The most prevalent deep intronic variant was c.1199+502A>T, followed by c.1065+241C>A, c.1065+258C>A, and c.706+531T>C. The metabolic phenotypes of the four variants were assigned as classic PKU, mild HPA, mild HPA, and mild PKU, respectively. The results suggest that deep intronic PAH variants improved the diagnostic rate from 95.3% to 99.3% in the overall patients with HPA. Our data demonstrate the importance of assessing noncoding variants in genetic diseases. Pseudoexon inclusion caused by deep intronic variants could represent a recurrent mechanism.
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Affiliation(s)
- Xiaomei Luo
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Ruifang Wang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Yu Sun
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Wenjuan Qiu
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Deyun Lu
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Yu Wang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Zhuwen Gong
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Huiwen Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Lianshu Han
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Lili Liang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Xuefan Gu
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China
| | - Yongguo Yu
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China.
| | - Bing Xiao
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Institute for Pediatric Research, Shanghai, China.
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8
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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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9
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Lin Y, Lin W, Su R, Zheng Z, Fu Q, Wang G. Newborn screening and genetic features of patients with hyperphenylalaninemia in a southern Chinese population. Clin Chim Acta 2022; 535:13-18. [PMID: 35952926 DOI: 10.1016/j.cca.2022.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/28/2022] [Accepted: 08/05/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND AIMS Hyperphenylalaninemia (HPA) is the most common congenital amino acid metabolism-related defect, but its incidence differs substantially between northern and southern China. We aimed to elucidate the incidence, proportion, and genetic features of HPA in a southern Chinese population. MATERIALS AND METHODS We analyzed the HPA screening results for 580,460 newborns from 2014 to 2021. RESULTS Of the 296 newborns who tested HPA positive, 56 were diagnosed with HPA, including 47 with phenylalanine hydroxylase deficiency and nine with tetrahydrobiopterin deficiency (BH4D). HPA incidence was estimated to be 1:10,365 newborns. All patients had elevated Phe and Phe/Tyr levels. Thirty-three PAH variants and five PTS variants were detected in HPA patients; 80.6 % PAH variants and 100 % PTS variants were classified as pathogenic or likely pathogenic. In silico tools predicted the remaining variants to be damaging. PAH variants clustered in exons 3, 5, 7, 11, and 12 and PTS variants clustered in exons 2 and 5. The most common PAH variants were c.158G > A (p.R53H, 22.3 %) and c.721C > T (p.R241C, 14.9 %). The most common PTS variants were c.155A > G (p.N52S, 50.0 %) and c.259C > T (p.P87S, 33.3 %). CONCLUSION Newborn screening is an effective method for early detection of HPA, but differential diagnosis of BH4D is necessary.
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Affiliation(s)
- Yiming Lin
- Center of Neonatal Disease Screening, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Weihua Lin
- Center of Neonatal Disease Screening, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Run Su
- Center of Neonatal Disease Screening, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Zhenzhu Zheng
- Center of Neonatal Disease Screening, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Qingliu Fu
- Center of Neonatal Disease Screening, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China.
| | - Gaoxiong Wang
- Department of Surgery, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China.
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10
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Compound Heterozygosis in AADC Deficiency and Its Complex Phenotype in Terms of AADC Protein Population. Int J Mol Sci 2022; 23:ijms231911238. [PMID: 36232540 PMCID: PMC9570296 DOI: 10.3390/ijms231911238] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/21/2022] [Accepted: 09/22/2022] [Indexed: 11/16/2022] Open
Abstract
Aromatic amino acid decarboxylase (AADC) deficiency is a rare monogenic disease due to mutations in the ddc gene producing AADC, a homodimeric pyridoxal 5′-phosphate-dependent enzyme. The disorder is often fatal in the first decade and is characterized by profound motor impairments and developmental delay. In the last two years, there has been a net rise in the number of patients and variants identified, maybe also pushed by the ongoing gene therapy trials. The majority of the identified genotypes are compound heterozygous (about 70%). Efforts are underway to reach early diagnosis, find possible new markers/new fast methods, and predict clinical outcome. However, no clear correlation of genotype-to-phenotype exists to date. Nevertheless, for homozygous patients, reliable results have been obtained using genetic methods combined with available computational tools on crystal structures corroborated by biochemical investigations on recombinant homodimeric AADC variants that have been obtained and characterized in solution. For these variants, the molecular basis for the defect has been suggested and validated, since it correlates quite well with mildness/severity of the homozygous phenotype. Instead, prediction for compound heterozygous patients is more difficult since complementation effects could happen. Here, by analyzing the existing literature on compound heterozygosity in AADC deficiency and other genetic disorders, we highlight that, in order to assess pathogenicity, the measurement of activity of the AADC heterodimeric variant should be integrated by bioinformatic, structural, and functional data on the whole protein constellation theoretically present in such patients. A wider discussion on symptomatic heterozygosity in AADC deficiency is also presented.
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11
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A capillary electrophoresis-based multiplex PCR assay for expanded carrier screening in the eastern Han Chinese population. NPJ Genom Med 2022; 7:6. [PMID: 35079019 PMCID: PMC8789796 DOI: 10.1038/s41525-021-00280-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 12/20/2021] [Indexed: 12/05/2022] Open
Abstract
Expanded carrier screening, a type of reproductive genetic testing for couples, has gained tremendous popularity for assessing the risk of passing on certain genetic conditions to offspring. Here, a carrier screening assay for 448 pathogenic variants was developed using capillary electrophoresis-based multiplex PCR technology. The capillary electrophoresis-based multiplex PCR assay achieved a sensitivity, specificity, and accuracy of 97.4%, 100%, and 99.6%, respectively, in detecting the specific variants. Among the 1915 couples (3830 individuals), 708 individuals (18.5%) were identified as carriers for at least one condition. Of the 708 carriers, 633 (89.4%) were heterozygous for one condition, 71 (10.0%) for two disorders, 3 (0.4%) for three disorders, and 1 (0.1%) for four disorders. Meanwhile, 30 (1.57%) couples were identified as at‐risk couples. This study describes an inexpensive and effective method for expanded carrier screening. The simplicity and accuracy of this approach will facilitate the clinical implementation of expanded carrier screening.
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12
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Characterization of phenylalanine hydroxylase gene variants and analysis of genotype-phenotype correlation in patients with phenylalanine hydroxylase deficiency from Fujian Province, Southeastern China. Mol Biol Rep 2022; 49:10409-10419. [PMID: 36104584 PMCID: PMC9618490 DOI: 10.1007/s11033-022-07579-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 05/06/2022] [Indexed: 11/18/2022]
Abstract
BACKGROUND Phenylalanine hydroxylase deficiency (PAHD) is the most prevalent inherited disorder of amino acid metabolism in China. Its complex phenotype includes many variants and genotypes among different populations. METHODS AND RESULTS In this study, we analyzed the phenylalanine hydroxylase gene (PAH) variants in a cohort of 93 PAHD patients from Fujian Province. We also assessed genotype and phenotype correlation in patients with PAHD. A total of 44 different pathogenic variants were identified, including five novel variants. The three most prevalent variants among all patents were c.158G > A, p.(Arg53His) (18.03%), c.721C > T, p.(Arg241Cys) (14.75%), and c.728G > A, p.(Arg243Gln) (7.65%). The frequency of the c.158G > A, p.(Arg53His) variant was highest in patients with mild hyperphenylalaninemia, whereas the frequency of the c.1197A > T, p.(Val399 =) and c.331C > T, p.(Arg111Ter) variants was highest in patients with classic phenylketonuria. The most abundant genotypes observed in PAHD patients were c.[158G > A];[728G > A], c.[158G > A];[442-1G > A], and c.[158G > A];[721C > T]. Comparing allelic phenotype to genotypic phenotype values yielded fairly accurate predictions of phenotype, with an overall consistency rate was 85.71% for PAHD patients. CONCLUSIONS Our study identified a PAH variant spectrum in PAHD patients from Fujian Province, Southeastern China. Quantitative correlation analysis between genotype and phenotype severity is helpful for genetic counseling and management.
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13
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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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14
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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, Belmont-Martínez L, Fernández-Lainez C. An Updated PAH Mutational Spectrum of Phenylketonuria in Mexican Patients Attending a Single Center: Biochemical, Clinical-Genotyping Correlations. Genes (Basel) 2021; 12:genes12111676. [PMID: 34828281 PMCID: PMC8620669 DOI: 10.3390/genes12111676] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 11/21/2022] Open
Abstract
Establishing the genotypes of patients with hyperphenylalaninemia (HPA)/phenylketonuria (PKU, MIM#261600) has been considered a cornerstone for rational medical management. However, knowledge of the phenylalanine hydroxylase gene (PAH) mutational spectrum in Latin American populations is still limited. Herein, we aim to update the mutational PAH spectrum in the largest cohort of HPA/PKU Mexican patients (N = 124) reported to date. The biallelic PAH genotype was investigated by Sanger automated sequencing, and genotypes were correlated with documented biochemical phenotypes and theoretical tetrahydrobiopterin (BH4) responsiveness. Patients were biochemically classified as having classic PKU (50%, 62/124), mild PKU (20.2%, 25/124) and mild HPA (29.8%, 37/124). Furthermore, 78.2% of the included patients (97/124) were identified by newborn screening. A total of 60 different pathogenic variants were identified, including three novel ones (c. 23del, c. 625_626insC and c. 1315 + 5_1315 + 6insGTGTAACAG), the main categories being missense changes (58%, 35/60) and those affecting the catalytic domain (56.6%, 34/60), and c. 60 + 5G > T was the most frequent variant (14.5%, 36/248) mainly restricted (69.2%) to patients from the central and western parts of Mexico. These 60 types of variants constituted 100 different biallelic PAH genotypes, with the predominance of compound-heterozygous ones (96/124, 77%). The expected BH4 responsiveness based on the PAH genotype was estimated in 52% of patients (65/124), mainly due to the p. (Val388Met) (rs62516101) allele. Instead, our study identified 27 null variants with an allelic phenotype value of zero, with a predominance of c. 60 + 5G > T, which predicts the absence of BH4 responsiveness. An identical genotype reported in BIOPKUdb was found in 92/124 (74%) of our patients, leading to a genotype–phenotype concordance in 80/92 (86.9%) of them. The high number of variants found confirms the heterogeneous and complex mutational landscape of HPA/PKU in Mexico.
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Affiliation(s)
- Marcela Vela-Amieva
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Miguel Angel Alcántara-Ortigoza
- Laboratorio de Biología Molecular, Subdirección de Investigación Médica, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.A.A.-O.); (A.G.-d.A.); (L.F.-H.)
| | - Isabel Ibarra-González
- Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas, UNAM/Instituto Nacional de Pediatría, Ciudad de Mexico 04530, Mexico;
| | - Ariadna González-del Angel
- Laboratorio de Biología Molecular, Subdirección de Investigación Médica, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.A.A.-O.); (A.G.-d.A.); (L.F.-H.)
| | - Liliana Fernández-Hernández
- Laboratorio de Biología Molecular, Subdirección de Investigación Médica, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.A.A.-O.); (A.G.-d.A.); (L.F.-H.)
| | - Sara Guillén-López
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Lizbeth López-Mejía
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Rosa Itzel Carrillo-Nieto
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Leticia Belmont-Martínez
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Cynthia Fernández-Lainez
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
- Correspondence: ; Tel.: +52-1-55-10840900 (ext. 1332)
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15
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Gundorova P, Kuznetcova IA, Baydakova GV, Stepanova AA, Itkis YS, Kakaulina VS, Alferova IP, Lyazina LV, Andreeva LP, Kanivets I, Zakharova EY, Kutsev SI, Polyakov AV. BH4-deficient hyperphenylalaninemia in Russia. PLoS One 2021; 16:e0249608. [PMID: 33822819 PMCID: PMC8023510 DOI: 10.1371/journal.pone.0249608] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/22/2021] [Indexed: 02/07/2023] Open
Abstract
A timely detection of patients with tetrahydrobiopterin (BH4) -deficient types of hyperphenylalaninemia (HPABH4) is important for assignment of correct therapy, allowing to avoid complications. Often HPABH4 patients receive the same therapy as phenylalanine hydroxylase (PAH) -deficiency (phenylketonuria) patients—dietary treatment—and do not receive substitutive BH4 therapy until the diagnosis is confirmed by molecular genetic means. In this study, we present a cohort of 30 Russian patients with HPABH4 with detected variants in genes causing different types of HPA. Family diagnostics and biochemical urinary pterin spectrum analyses were carried out. HPABH4A is shown to be the prevalent type, 83.3% of all HPABH4 cases. The mutation spectrum for the PTS gene was defined, the most common variants in Russia were p.Thr106Met—32%, p.Asn72Lys—20%, p.Arg9His—8%, p.Ser32Gly—6%. We also detected 7 novel PTS variants and 3 novel QDPR variants. HPABH4 prevalence was estimated to be 0.5–0.9% of all HPA cases in Russia, which is significantly lower than in European countries on average, China, and Saudi Arabia. The results of this research show the necessity of introducing differential diagnostics for HPABH4 into neonatal screening practice.
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Affiliation(s)
| | | | | | | | | | - Victoria S. Kakaulina
- Federal State Budgetary Institution of Medical Department of Moscow “Morozov Children’s City Clinical Hospital of Medical Department of Moscow”, Moscow, Russia
| | - Irina P. Alferova
- Municipal Autonomous Health Care Institution of the Order of the Red Banner of Labor “Clinical Hospital № 1”, Chelyabinsk, Russia
| | - Lidya V. Lyazina
- Saint Petersburg State Public Health Institution "Medical Genetic Diagnostic Center”, Saint Petersburg, Russia
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16
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Development of a mutation hotspot detection kit for the phenylalanine hydroxylase gene by ARMS-PCR combined with fluorescent probe technology. Biosci Rep 2021; 41:227829. [PMID: 33564846 PMCID: PMC7897920 DOI: 10.1042/bsr20201660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 01/24/2021] [Accepted: 02/09/2021] [Indexed: 11/17/2022] Open
Abstract
To develop a screening kit for detecting mutation hotspots of the phenylalanine hydroxylase (PAH) gene. Thirteen exons of the PAH gene were sequenced in 84 cases with phenylketonuria (PKU) diagnosed during neonatal genetic and metabolic disease screening in Shaanxi province, and their mutations were analyzed. We designed and developed a screening kit to detect nine mutation sites covering more than 50% of the PAH mutations found in Shaanxi province (c.728G>A, c.1197A>T, c.331C>T, c.1068C>A, c.611A>G, c.1238G>C, c.721C>T, c.442-1G>A, and c.158G>A) by using amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) combined with fluorescent probe technology. Peripheral blood and dried blood samples from PKU families were used for clinical verification of the newly developed kit. PAH gene mutations were detected in 84 children diagnosed with PKU. A total of 159 mutant alleles were identified, consisting of 100 missense mutations, 28 shear mutations, 24 nonsense mutations, and 7 deletion mutations. Exon 7 had the highest mutation frequency (32.08%). Among them, the mutation frequency of p.R243Q was the highest, accounting for 20.13% of all mutations, followed by p.R111X, IVS4-1G>A, EX6-96A>G, and p.R413P; these five loci accounted for 47.17% (75/159) of all mutations. In addition, we identified three previously unreported PAH gene mutations (p.C334X, p.G46D, and p.G256D). Fifteen mutation sites were identified in the 47 PAH carriers identified by next-generation sequencing (NGS), which were verified by the newly developed kit, with an agreement rate of 100%. This newly developed kit based on ARMS-PCR combined with fluorescent probe technology can be used to detect common PAH gene mutations.
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17
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Tao Y, Han D, Shen H, Li X. Spectrum of PAH gene mutations and genotype-phenotype correlation in patients with phenylalanine hydroxylase deficiency from Shanxi province. Brain Dev 2021; 43:220-229. [PMID: 32893076 DOI: 10.1016/j.braindev.2020.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/04/2020] [Accepted: 08/18/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Phenylalanine hydroxylase deficiency (PAHD) is an autosomal recessive inborn error that affects phenylalanine (Phe) metabolism. It has a complex phenotype with many variants and genotypes among different populations. Shanxi province is a high-prevalence area of PAHD in China. METHODS In this study, eighty-nine PAHD patients were subjected to genetic testing using Sanger sequencing, followed by multiplex ligation-dependent probe amplification analysis (MLPA). Allelic and genotypic phenotype values (APV and GPV, respectively) were used for genotype-based phenotypic prediction. RESULTS Fifty-one types of variants, including three novel forms, were identified. The predominant variant was p.R243Q (22.09%), followed by p.R53H (10.47%), p.EX6-96A > G (9.30%), p.V399V (5.23%) and p.R413P (3.49%). Notably, mild hyperphenylalaninemia (MHP) has a high prevalence in this region (up to 45.76%), and the variant p.R53H was solely observed in patients of MHP. According to the genotype-phenotype prediction, the APV/GPV system was well correlated with the metabolic phenotype of most PAHD patients. CONCLUSION We have systematically constructed the mutational and phenotypic spectrum of PAH in Shanxi province. Hence, this study will help to further understand the genotype-phenotype associations in PAHD patients, and it may offer more reliable genetic counseling and management.
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Affiliation(s)
- Yilun Tao
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China
| | - Dong Han
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China
| | - Huiyi Shen
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China
| | - Xiaoze Li
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China.
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18
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Kuznetcova I, Gundorova P, Ryzhkova O, Polyakov A. The study of the full spectrum of variants leading to hyperphenylalaninemia have revealed 10 new variants in the PAH gene. Metab Brain Dis 2019; 34:1547-1555. [PMID: 31332730 DOI: 10.1007/s11011-019-00461-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/08/2019] [Indexed: 12/21/2022]
Abstract
This study presents further research into the spectrum of variants in genes responsible for the development of phenylketonuria (PKU) and hyperphenylalaninemia (HPA) in patients in Russia. After a study of 25 frequent variants, 293 patients (327 chromosomes without detected variants) from among 1265 probands still had no confirmed diagnosis. A study involving methods of next generation sequencing (NGS) of PAH, PTS, GCH1, PCBD1, QDPR, SPR and DNAJC12 genes to search for point mutations and multiplex ligation-dependent probe amplification (MLPA) methods to search for gross deletions were conducted for these patients. Among 327 chromosomes without identified variants, variants in the PAH gene were found on 260 chromosomes, and variants in the PTS gene were found on 10 chromosomes. On 10 chromosomes gross deletions by the MLPA method were detected. 104 rare variants of the РАН gene, including 10 variants not previously described, and 6 variants of the PTS gene were revealed. The NGS method revealed additional РАН gene variants on 10.3% of chromosomes and PTS gene variants on 0.4%. Gross deletions of the РАН gene were revealed in 0.5% of chromosomes. Thus, the most complete understanding of the spectrum of variants leading to the development of the PKU and HPA in Russia with the use of all methods available today has been obtained. Such a detailed study of the spectrum of rare variants on the genetic material from Russia was undertaken for the first time.
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Affiliation(s)
- I Kuznetcova
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation.
| | - P Gundorova
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation
| | - O Ryzhkova
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation
| | - A Polyakov
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation
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Wang T, Ma J, Zhang Q, Gao A, Wang Q, Li H, Xiang J, Wang B. Expanded Newborn Screening for Inborn Errors of Metabolism by Tandem Mass Spectrometry in Suzhou, China: Disease Spectrum, Prevalence, Genetic Characteristics in a Chinese Population. Front Genet 2019; 10:1052. [PMID: 31737040 PMCID: PMC6828960 DOI: 10.3389/fgene.2019.01052] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 10/01/2019] [Indexed: 12/30/2022] Open
Abstract
Expanded newborn screening for inborn errors of metabolism (IEMs) by tandem mass spectrometry (MS/MS) could simultaneously analyze more than 40 metabolites and identify about 50 kinds of IEMs. Next generation sequencing (NGS) targeting hundreds of IMEs-associated genes as a follow-up test in expanded newborn screening has been used for genetic analysis of patients. The spectrum, prevalence, and genetic characteristic of IEMs vary dramatically in different populations. To determine the spectrum, prevalence, and gene mutations of IEMs in newborns in Suzhou, China, 401,660 newborns were screened by MS/MS and 138 patients were referred to genetic analysis by NGS. The spectrum of 22 IEMs were observed in Suzhou population of newborns, and the overall incidence (excluding short chain acyl-CoA dehydrogenase deficiency (SCADD) and 3-Methylcrotonyl-CoA carboxylase deficiency (3-MCCD)) was 1/3,163. The prevalence of each IEM ranged from 1/401,660 to 1/19,128, while phenylketonuria (PKU) (1/19,128) and Mild hyperphenylalaninemia (M-HPA) (1/19,128) were the most common IEMs, followed by primary carnitine uptake defect (PCUD) (1/26,777), SCADD (1/28,690), hypermethioninemia (H-MET) (1/30,893), 3-MCCD (1/33,412) and methylmalonic acidemia (MMA) (1/40,166). Moreover, 89 reported mutations and 51 novel mutations in 25 IMEs-associated genes were detected in 138 patients with one of 22 IEMs. Some hotspot mutations were observed for ten IEMs, including PAH gene c.728G > A, c.611A > G, and c.721C > T for Phenylketonuria, PAH gene c.158G > A, c.1238G > C, c.728G > A, and c.1315+6T > A for M-HPA, SLC22A5 gene c.1400C > G, c.51C > G, and c.760C > T for PCUD, ACADS gene c.1031A > G, c.164C > T, and c.1130C > T for SCAD deficiency, MAT1A gene c.791G > A for H-MET, MCCC1 gene c.639+2T > A and c.863A > G for 3-MCCD, MMUT gene c.1663G > A for MMA, SLC25A13 gene c.IVS16ins3Kb and c.852_855delTATG for cittrullinemia II, PTS gene c.259C > T and c.166G > A for Tetrahydrobiopterin deficiency, and ACAD8 gene c.1000C > T and c.286C > A for Isobutyryl coa dehydrogenase deficiency. All these hotspot mutations were reported to be pathogenic or likely pathogenic, except a novel mutation of ACAD8 gene c.286C > A. These mutational hotspots could be potential candidates for gene screening and these novel mutations expanded the mutational spectrum of IEMs. Therefore, our findings could be of value for genetic counseling and genetic diagnosis of IEMs.
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Affiliation(s)
- Ting Wang
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Jun Ma
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Qin Zhang
- Genetic Clinic, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Ang Gao
- Genetic Clinic, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Qi Wang
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Hong Li
- Infertility Clinic, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Jingjing Xiang
- Genetic Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Benjing Wang
- Newborn Screening Laboratory, Center for Reproduction and Genetics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
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Almannai M, Felemban R, Saleh MA, Faqeih EA, Alasmari A, AlHashem A, Mohamed S, Sunbul R, Al-Murshedi F, AlThihli K, Eyaid W, Ali R, Ben-Omran T, Blau N, El-Hattab AW, Alfadhel M. 6-Pyruvoyltetrahydropterin Synthase Deficiency: Review and Report of 28 Arab Subjects. Pediatr Neurol 2019; 96:40-47. [PMID: 30926181 DOI: 10.1016/j.pediatrneurol.2019.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 02/03/2019] [Accepted: 02/10/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND Tetrahydrobiopterin is an essential cofactor for the hydroxylation of aromatic amino acids phenylalanine, tyrosine, and tryptophan. Therefore, tetrahydrobiopterin deficiency results in hyperphenylalaninemia as well as dopamine and serotonin depletion in the central nervous system. The enzyme 6-pyruvoyltetrahydropterin synthase catalyzes the second step of de novo synthesis of tetrahydrobiopterin, and its deficiency is the most frequent cause of tetrahydrobiopterin metabolism disorders. METHOD We conducted a retrospective chart review of 28 subjects from 24 families with molecularly confirmed 6-pyruvoyltetrahydropterin synthase deficiency from six centers in three Arab countries. We reviewed clinical, biochemical, and molecular data. We also reviewed previously published cohorts of subjects with 6-pyruvoyltetrahydropterin synthase deficiency. RESULTS Similar to previous observations, we show that early treatment (less than two months) is associated with better outcome. We identify eight PTS variants in 24 independent families. The most common variant is (c.238A>G; p.M80V) with an allele count of 33%. We also identify one novel variant (c.2T>G; p.?). CONCLUSION The deficiency of 6-pyruvoyltetrahydropterin synthase is relatively common in the Arab population and should be considered in individuals with hyperphenylalaninemia. More natural history studies with comprehensive biochemical and molecular genetics data are needed for a robust base for the development of future therapy.
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Affiliation(s)
- Mohammed Almannai
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Rana Felemban
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Mohammed A Saleh
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Eissa A Faqeih
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ali Alasmari
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Amal AlHashem
- Department of Pediatric, Prince Sultan Medical Military City, Riyadh, Saudi Arabia; Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Sarar Mohamed
- Department of Pediatric, Prince Sultan Medical Military City, Riyadh, Saudi Arabia
| | - Rawda Sunbul
- Pediatrics Medical Genetic Unit (PMGU), Pediatrics Department, Qatif Central Hospital, Qatif, Saudi Arabia
| | - Fathiya Al-Murshedi
- Department of Genetics, College of Medicine, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Khalid AlThihli
- Department of Genetics, College of Medicine, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Wafaa Eyaid
- Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Rehab Ali
- Clinical and Metabolic Genetics Section, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - Tawfeg Ben-Omran
- Clinical and Metabolic Genetics Section, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - Nenad Blau
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany; Division of Metabolism, University Children's Hospital Zurich, Switzerland
| | - Ayman W El-Hattab
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates; Genetics Clinics, KidsHeart Medical Center, Dubai, United Arab Emirates
| | - Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), Riyadh, Saudi Arabia; College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
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21
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In vitro residual activities in 20 variants of phenylalanine hydroxylase and genotype-phenotype correlation in phenylketonuria patients. Gene 2019; 707:239-245. [PMID: 31102715 DOI: 10.1016/j.gene.2019.05.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 04/12/2019] [Accepted: 05/13/2019] [Indexed: 11/21/2022]
Abstract
Phenylketonuria (PKU), caused by phenylalanine hydroxylase (PAH) gene variants, is a common autosomal inherited metabolic disease. So far, 1111 PAH variants have been revealed. The residual activity of the PAH variants is the key determinant of the metabolic phenotype and BH4 responsiveness in PKU patients. In this study, the spectrum of PAH variants in 1083 Chinese PKU patients was analyzed. Then 20 variants (p.L52F, p.R86P, p.L128P, p.L142P, p.D163N, p.C203G, p.E214G, p.F260L, p.M276T, p.L311R, p.P314A, p.L364F, p.Q375H, p.F382I, p.A395S, p.V412D, p.E108*, p.C203*, p.C284* and p.E353*) were expressed in COS-7 cells. The residual activities and protein expression levels were detected by isotope-dilution liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) and Western blotting, respectively. We compared the results of the phenotypic prediction based on APV and PAH activity respectively, and further explored the relationship between residual activity and phenotype in PKU patients. We reported 9 newly discovered PAH variants for the first time, thereby expanding the spectrum of PAH variants. Among the 20 variants in our assay, 8 variants showed mild impaired residual activities (48-92%) and approximately normal protein expression levels compared to the wild-type PAH. In contrast, 9 variants showed severely impaired residual activities (0-34%) and reduced protein expression. However, three variants (p.L52F, p.F260L and p.P314A) showed impaired residual activities (5%, 32% and 29%), although the proteins were well expressed. We assigned APV scores for 14 variants, in which the results of the phenotypic prediction were consistent for 12/14 (86%) variants based on APV and residual activity respectively, and the residual activity correctly predicted 17/22 (77%) of the patients. Our study helped to further understand the genotype-phenotype correlation in PKU patients.
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22
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Kure S, Shintaku H. Tetrahydrobipterin-responsive phenylalanine hydroxylase deficiency. J Hum Genet 2019; 64:67-71. [PMID: 30504912 DOI: 10.1038/s10038-018-0529-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/16/2018] [Accepted: 10/19/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Shigeo Kure
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan.
| | - Haruo Shintaku
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka, Japan
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Himmelreich N, Shen N, Okun JG, Thiel C, Hoffmann GF, Blau N. Relationship between genotype, phenylalanine hydroxylase expression and in vitro activity and metabolic phenotype in phenylketonuria. Mol Genet Metab 2018; 125:86-95. [PMID: 30037505 DOI: 10.1016/j.ymgme.2018.06.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/21/2018] [Accepted: 06/22/2018] [Indexed: 01/22/2023]
Abstract
Residual phenylalanine hydroxylase (PAH) activity is the main determinant of the metabolic phenotype in phenylketonuria (PKU). The genotypic heterogeneity of PKU, involving >1000 PAH variants and over 2500 different genotypes, makes genotype-based phenotype prediction challenging. While a relationship between PAH variants and the metabolic phenotype is well established, we questioned the importance of PAH expression and residual in vitro activity for the metabolic phenotype. Thirty-four PAH variants (p.F39 L, p.A47V, p.D59Y, p.I65S, p.R68G, p.R68S, p.E76G, p.A104D, p.D143G, p.R155H, p.R176L, p.V190A, p.G218 V, p.R241C, p.R243Q, p.P244L, p.R252W, p.R261Q, p.E280K, p.R297H, p.A300S, p.I306V, p.A309V, p.L311P, p.A313T, p.L348 V, p.V388 M, A403V, p.R408Q, p.R408W, p.R413P, p.D415N, p.Y417H, and p.A434D) were transiently transfected into COS-7 cells, and expression of PAH was investigated. Expression patterns were compared with in vitro PAH activity and allelic phenotype values (APVs). In vitro PAH activity was significantly higher (p < .01) in variants associated with mild hyperphenylalaninemia (PAH activity = 52.1 ± 8.5%; APV = 6.7-10.0) than that in classic PKU variants (PAH activity = 21.1 ± 7.0%; APV = 0-2.7). Mild PKU variants (PAH activity = 40.2 ± 7.6%; APV = 2.8-6.6) were not significantly different from mild hyperphenylalaninemia, but there was a difference (p < .048) compared with classic PKU phenotypes.
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Affiliation(s)
- Nastassja Himmelreich
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Nan Shen
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany; Department of Rehabilitation Medicine, Xin Hua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jürgen G Okun
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Christian Thiel
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Nenad Blau
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany.
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