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Shen G, Li W, Zhang Y, Chen L. Next-generation sequencing based newborn screening and comparative analysis with MS/MS. BMC Pediatr 2024; 24:230. [PMID: 38561707 PMCID: PMC10985934 DOI: 10.1186/s12887-024-04718-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 03/21/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Newborn screening (NBS), such as tandem mass spectrometry (MS/MS), may yield false positive/negative results. Next-generation sequencing (NGS) has the potential to provide increased data output, efficiencies, and applications. This study aimed to analyze the types and distribution of pathogenic gene mutations in newborns in Huzhou, Zhejiang province, China and explore the applicability of NGS and MS/MS in NBS. METHODS Blood spot samples from 1263 newborns were collected. NGS was employed to screen for pathogenic variants in 542 disease-causing genes, and detected variants were validated using Sanger sequencing. Simultaneously, 26 inherited metabolic diseases (IMD) were screened using MS/MS. Positive or suspicious samples identified through MS/MS were cross-referenced with the results of NGS. RESULTS Among all newborns, 328 had no gene mutations detected. NGS revealed at least one gene mutation in 935 newborns, with a mutation rate of 74.0%. The top 5 genes were FLG, GJB2, UGT1A1, USH2A, and DUOX2. According to American College of Medical Genetics guidelines, gene mutations in 260 cases were classified as pathogenic or likely pathogenic mutation, with a positive rate of 20.6%. The top 5 genes were UGT1A1, FLG, GJB2, MEFV, and G6PD. MS/MS identified 18 positive or suspicious samples for IMD and 1245 negative samples. Verification of these cases by NGS results showed no pathogenic mutations, resulting in a false positive rate of 1.4% (18/1263). CONCLUSION NBS using NGS technology broadened the range of diseases screened, and enhanced the accuracy of diagnoses in comparison to MS/MS for screening IMD. Combining NGS and biochemical screening would improve the efficiency of current NBS.
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Affiliation(s)
- Guosong Shen
- Medical Laboratory Center, Huzhou Maternity & Child Health Care Hospital, Huzhou, Zhejiang Province, 313000, China.
| | - Wenwen Li
- Medical Laboratory Center, Huzhou Maternity & Child Health Care Hospital, Huzhou, Zhejiang Province, 313000, China
| | - Yaqin Zhang
- Medical Laboratory Center, Huzhou Maternity & Child Health Care Hospital, Huzhou, Zhejiang Province, 313000, China
| | - Lyuyan Chen
- Institut for Neuroscience, Technical University of Munich, 80802, Munich, Germany
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2
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Long MT, Kruser JM, Quinonez SC. Urea cycle disorders in critically Ill adults. Curr Opin Clin Nutr Metab Care 2024; 27:184-191. [PMID: 37938118 DOI: 10.1097/mco.0000000000000992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
PURPOSE OF REVIEW Urea cycle disorders (UCDs) cause elevations in ammonia which, when severe, cause irreversible neurologic injury. Most patients with UCDs are diagnosed as neonates, though mild UCDs can present later - even into adulthood - during windows of high physiologic stress, like critical illness. It is crucial for clinicians to understand when to screen for UCDs and appreciate how to manage these disorders in order to prevent devastating neurologic injury or death. RECENT FINDINGS Hyperammonemia, particularly if severe, causes time- and concentration-dependent neurologic injury. Mild UCDs presenting in adulthood are increasingly recognized, so broader screening in adults is recommended. For patients with UCDs, a comprehensive, multitiered approach to management is needed to prevent progression and irreversible injury. Earlier exogenous clearance is increasingly recognized as an important complement to other therapies. SUMMARY UCDs alter the core pathway for ammonia metabolism. Screening for mild UCDs in adults with unexplained neurologic symptoms can direct care and prevent deterioration. Management of UCDs emphasizes decreasing ongoing ammonia production, avoiding catabolism, and supporting endogenous and exogenous ammonia clearance. Core neuroprotective and supportive critical care supplements this focused therapy.
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Affiliation(s)
- Micah T Long
- Departments of Anesthesiology & Internal Medicine, University of Wisconsin Hospitals and Clinics
| | - Jacqueline M Kruser
- Department of Medicine, University of Wisconsin Hospitals and Clinics, Madison, Wisconsin
| | - Shane C Quinonez
- Departments of Pediatrics and Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
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3
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Rojas CR, Chapman J, Regier D. Hyperammonemia in the Pediatric Emergency Department. Pediatr Emerg Care 2024; 40:156-161. [PMID: 38295195 DOI: 10.1097/pec.0000000000003121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
ABSTRACT Hyperammonemia is a serious clinical condition associated with significant morbidity and mortality. In the pediatric population, this is often caused by urea cycle disorders, acute liver failure, or other less common underlying etiologies. Children and teens with hyperammonemia can have a broad range of clinical findings, including vomiting, respiratory distress, and changes in mental status. As ammonia levels worsen, this presentation can progress to respiratory failure, encephalopathy, cerebral edema, seizures, and death. Given the risk of neurologic damage, timely identification and management of hyperammonemia is critical and includes initial resuscitation, early consultation with subspecialists, and initiation of appropriate therapies. It is important for pediatric emergency medicine providers to understand the clinical findings, causes, diagnosis, and management of hyperammonemia because they play a key role in the provision of effective, multidisciplinary care of these patients.
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4
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Lo RS, Cromie GA, Tang M, Teng K, Owens K, Sirr A, Kutz JN, Morizono H, Caldovic L, Ah Mew N, Gropman A, Dudley AM. The functional impact of 1,570 individual amino acid substitutions in human OTC. Am J Hum Genet 2023; 110:863-879. [PMID: 37146589 PMCID: PMC10183466 DOI: 10.1016/j.ajhg.2023.03.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/30/2023] [Indexed: 05/07/2023] Open
Abstract
Deleterious mutations in the X-linked gene encoding ornithine transcarbamylase (OTC) cause the most common urea cycle disorder, OTC deficiency. This rare but highly actionable disease can present with severe neonatal onset in males or with later onset in either sex. Individuals with neonatal onset appear normal at birth but rapidly develop hyperammonemia, which can progress to cerebral edema, coma, and death, outcomes ameliorated by rapid diagnosis and treatment. Here, we develop a high-throughput functional assay for human OTC and individually measure the impact of 1,570 variants, 84% of all SNV-accessible missense mutations. Comparison to existing clinical significance calls, demonstrated that our assay distinguishes known benign from pathogenic variants and variants with neonatal onset from late-onset disease presentation. This functional stratification allowed us to identify score ranges corresponding to clinically relevant levels of impairment of OTC activity. Examining the results of our assay in the context of protein structure further allowed us to identify a 13 amino acid domain, the SMG loop, whose function appears to be required in human cells but not in yeast. Finally, inclusion of our data as PS3 evidence under the current ACMG guidelines, in a pilot reclassification of 34 variants with complete loss of activity, would change the classification of 22 from variants of unknown significance to clinically actionable likely pathogenic variants. These results illustrate how large-scale functional assays are especially powerful when applied to rare genetic diseases.
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Affiliation(s)
- Russell S Lo
- Pacific Northwest Research Institute, Seattle, WA, USA
| | | | - Michelle Tang
- Pacific Northwest Research Institute, Seattle, WA, USA
| | - Kevin Teng
- Pacific Northwest Research Institute, Seattle, WA, USA
| | - Katherine Owens
- Pacific Northwest Research Institute, Seattle, WA, USA; Department of Applied Mathematics, University of Washington, Seattle, WA, USA
| | - Amy Sirr
- Pacific Northwest Research Institute, Seattle, WA, USA
| | - J Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, WA, USA
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Nicholas Ah Mew
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Andrea Gropman
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA; Department of Neurology, Division of Neurogenetics and Neurodevelopmental Disabilities, Children's National Hospital, Washington, DC, USA; Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
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5
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Tise CG, Verscaj CP, Mendelsohn BA, Woods J, Lee CU, Enns GM, Stander Z, Hall PL, Cowan TM, Cusmano-Ozog KP. MT-ATP6 mitochondrial disease identified by newborn screening reveals a distinct biochemical phenotype. Am J Med Genet A 2023; 191:1492-1501. [PMID: 36883293 DOI: 10.1002/ajmg.a.63159] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/24/2023] [Accepted: 02/08/2023] [Indexed: 03/09/2023]
Abstract
Although decreased citrulline is used as a newborn screening (NBS) marker to identify proximal urea cycle disorders (UCDs), it is also a feature of some mitochondrial diseases, including MT-ATP6 mitochondrial disease. Here we describe biochemical and clinical features of 11 children born to eight mothers from seven separate families who were identified with low citrulline by NBS (range 3-5 μM; screening cutoff >5) and ultimately diagnosed with MT-ATP6 mitochondrial disease. Follow-up testing revealed a pattern of hypocitrullinemia together with elevated propionyl-(C3) and 3-hydroxyisovaleryl-(C5-OH) acylcarnitines, and a homoplasmic pathogenic variant in MT-ATP6 in all cases. Single and multivariate analysis of NBS data from the 11 cases using Collaborative Laboratory Integrated Reports (CLIR; https://clir.mayo.edu) demonstrated citrulline <1st percentile, C3 > 50th percentile, and C5-OH >90th percentile when compared with reference data, as well as unequivocal separation from proximal UCD cases and false-positive low citrulline cases using dual scatter plots. Five of the eight mothers were symptomatic at the time of their child(ren)'s diagnosis, and all mothers and maternal grandmothers evaluated molecularly and biochemically had a homoplasmic pathogenic variant in MT-ATP6, low citrulline, elevated C3, and/or elevated C5-OH. All molecularly confirmed individuals (n = 17) with either no symptoms (n = 12), migraines (n = 1), or a neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP) phenotype (n = 3) were found to have an A or U mitochondrial haplogroup, while one child with infantile-lethal Leigh syndrome had a B haplogroup.
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Affiliation(s)
- Christina G Tise
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Courtney P Verscaj
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Bryce A Mendelsohn
- Department of Medical Genetics, Kaiser Permanente Northern California, Oakland, California, USA
| | - Jeremy Woods
- Division of Medical Genetics, Stanford University, Stanford, California, USA.,Department of Medical Genetics and Metabolism, Valley Children's Healthcare, Madera, California, USA
| | - Chung U Lee
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Gregory M Enns
- Division of Medical Genetics, Stanford University, Stanford, California, USA
| | - Zinandré Stander
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Patricia L Hall
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Tina M Cowan
- Department of Pathology, Stanford University, Stanford, California, USA
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Veldman A, Kiewiet MBG, Heiner-Fokkema MR, Nelen MR, Sinke RJ, Sikkema-Raddatz B, Voorhoeve E, Westra D, Dollé MET, Schielen PCJI, van Spronsen FJ. Towards Next-Generation Sequencing (NGS)-Based Newborn Screening: A Technical Study to Prepare for the Challenges Ahead. Int J Neonatal Screen 2022; 8:ijns8010017. [PMID: 35323196 PMCID: PMC8949100 DOI: 10.3390/ijns8010017] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/28/2022] [Accepted: 02/08/2022] [Indexed: 01/27/2023] Open
Abstract
Newborn screening (NBS) aims to identify neonates with severe conditions for whom immediate treatment is required. Currently, a biochemistry-first approach is used to identify these disorders, which are predominantly inherited meta1bolic disorders (IMD). Next-generation sequencing (NGS) is expected to have some advantages over the current approach, for example the ability to detect IMDs that meet all screening criteria but lack an identifiable biochemical footprint. We have now designed a technical study to explore the use of NGS techniques as a first-tier approach in NBS. Here, we describe the aim and set-up of the NGS-first for the NBS (NGSf4NBS) project, which will proceed in three steps. In Step 1, we will identify IMDs eligible for NGS-first testing, based on treatability. In Step 2, we will investigate the feasibility, limitations and comparability of different technical NGS approaches and analysis workflows for NBS, eventually aiming to develop a rapid NGS-based workflow. Finally, in Step 3, we will prepare for the incorporation of this workflow into the existing Dutch NBS program and propose a protocol for referral of a child after a positive NGS test result. The results of this study will be the basis for an additional analytical route within NBS that will be further studied for its applicability within the NBS program, e.g., regarding the ethical, legal, financial and social implications.
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Affiliation(s)
- Abigail Veldman
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands;
- Correspondence: (A.V.); (M.B.G.K.)
| | - Mensiena B. G. Kiewiet
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands;
- Department of Genetics, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands; (R.J.S.); (B.S.-R.)
- Correspondence: (A.V.); (M.B.G.K.)
| | - Margaretha Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands;
| | - Marcel R. Nelen
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (M.R.N.); (D.W.)
| | - Richard J. Sinke
- Department of Genetics, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands; (R.J.S.); (B.S.-R.)
| | - Birgit Sikkema-Raddatz
- Department of Genetics, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands; (R.J.S.); (B.S.-R.)
| | - Els Voorhoeve
- Centre for Health Protection, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands; (E.V.); (M.E.T.D.)
| | - Dineke Westra
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands; (M.R.N.); (D.W.)
| | - Martijn E. T. Dollé
- Centre for Health Protection, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands; (E.V.); (M.E.T.D.)
| | - Peter C. J. I. Schielen
- Centre for Population Screening, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands;
| | - Francjan J. van Spronsen
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands;
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Ravindranath A, Sarma MS. Mitochondrial hepatopathy: Anticipated difficulties in management of fatty acid oxidation defects and urea cycle defects. World J Hepatol 2022; 14:180-194. [PMID: 35126847 PMCID: PMC8790400 DOI: 10.4254/wjh.v14.i1.180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/19/2021] [Accepted: 12/02/2021] [Indexed: 02/06/2023] Open
Abstract
Fatty acid oxidation defects (FAOD) and urea cycle defects (UCD) are among the most common metabolic liver diseases. Management of these disorders is dotted with challenges as the strategies differ based on the type and severity of the defect. In those with FAOD the cornerstone of management is avoiding hypoglycemia which in turn prevents the triggering of fatty acid oxidation. In this review, we discuss the role of carnitine supplementation, dietary interventions, newer therapies like triheptanoin, long-term treatment and approach to positive newborn screening. In UCD the general goal is to avoid excessive protein intake and indigenous protein breakdown. However, one size does not fit all and striking the right balance between avoiding hyperammonemia and preventing deficiencies of essential nutrients is a formidable task. Practical issues during the acute presentation including differential diagnosis of hyperammonemia, dietary dilemmas, the role of liver transplantation, management of the asymptomatic individual and monitoring are described in detail. A multi-disciplinary team consisting of hepatologists, metabolic specialists and dieticians is required for optimum management and improvement in quality of life for these patients.
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Affiliation(s)
- Aathira Ravindranath
- Division of Pediatric Gastroenterology, Institute of Gastrointestinal Sciences, Apollo BGS Hospitals, Mysore 570023, Karnataka, India
| | - Moinak Sen Sarma
- Pediatric Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, Uttar Pradesh, India
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Bin Sawad A, Jackimiec J, Bechter M, Hull M, Yeaw J, Wang Y, Diaz GA. Health care resource utilization in the management of patients with Arginase 1 Deficiency in the US: a retrospective, observational, claims database study. J Med Econ 2022; 25:848-856. [PMID: 35695271 DOI: 10.1080/13696998.2022.2089517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Arginase 1 Deficiency (ARG1-D) is an inherited metabolic disease that leads to significant morbidity. AIMS Despite the recognized burden of disease, information on health care resource utilization (HCRU) among patients with ARG1-D is lacking. We, therefore, sought to evaluate HCRU in ARG1-D relative to non-ARG1-D cohort. MATERIALS AND METHODS Patients with ≥2 ICD-10-CM diagnosis codes for ARG1-D were identified (first diagnosis code = index date) using professional fee claims linked with prescription claims. Patients with ARG1-D were matched 1:1 to a comparator cohort of patients with other medical conditions. Matching variables included age, sex, index year, payer type (Medicare, Medicaid, third party) and geographic region. RESULTS A total of 77 patients met the inclusion criteria for the ARG1-D cohort, with a median age of 15 years, 52% <18 years, and 52% male. Several concurrent diagnoses were recorded at a higher frequency in the ARG1-D cohort versus the matched comparator (spasticity 7 times higher; developmental delay ∼2 times higher; intellectual disability 5 times higher; and seizures 8 times higher). Emergency room visits occurred twice as often, laboratory tests were performed 1.5 times more often, hospitalization was required 3 times more often, and mean length of stay was longer for patients with ARG1-D than the comparator cohort (2.4 days vs. 0.3 days). LIMITATIONS A relatively short study period while the burden of ARG1-D increases over a lifetime due to disease progression. CONCLUSIONS Patients with ARG1-D had significantly greater HCRU compared with those without the disease; they presented with a more extensive comorbidity profile, accessed the health care system more frequently, required more intense monitoring and management, and had more frequent and longer hospitalizations relative to the comparator group. These findings demonstrate a high health burden in ARG1-D that is not mitigated by standard-of-care measures and emphasize the need for improved treatment options.
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Affiliation(s)
| | | | | | | | | | - Yi Wang
- IQVIA, Inc, Falls Church, VA, USA
| | - George A Diaz
- Division of Medical Genetics and Genomics in the Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Sen K, Harmon J, Gropman AL. Select Ethical Aspects of Next-Generation Sequencing Tests for Newborn Screening and Diagnostic Evaluation of Critically Ill Newborns. Int J Neonatal Screen 2021; 7:ijns7040076. [PMID: 34842609 PMCID: PMC8628939 DOI: 10.3390/ijns7040076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 12/26/2022] Open
Abstract
In this review, we analyze medical and select ethical aspects of the increasing use of next-generation sequencing (NGS) based tests in newborn medicine. In the last five years, there have been several studies exploring the role of rapid exome sequencing (ES) and genome sequencing (GS) in critically ill newborns. While the advantages include a high diagnostic yield with potential changes in interventions, there have been ethical dilemmas surrounding consent, information about adult-onset diseases and resolution of variants of uncertain significance. Another active area of research includes a cohort of studies funded under Newborn Sequencing in Genomic Medicine and Public Health pertaining to the use of ES and GS in newborn screening (NBS). While these techniques may allow for screening for several genetic disorders that do not have a detectable biochemical marker, the high costs and long turnaround times of these tests are barriers in their utilization as public health screening tests. Discordant results between conventional NBS and ES-based NBS, as well as challenges with consent, are other potential pitfalls of this approach. Please see the Bush, Al-Hertani and Bodamer article in this Special Issue for the broader scope and further discussion.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children’s National Hospital, Washington, DC 20010, USA;
| | - Jennifer Harmon
- Rare Disease Institute, Children’s National Hospital, Washington, DC 20010, USA;
| | - Andrea L. Gropman
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children’s National Hospital, Washington, DC 20010, USA;
- Correspondence: ; Tel.: +1-202-476-3511; Fax: +1-202-476-4336
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Lund AM, Wibrand F, Skogstrand K, Bækvad-Hansen M, Gregersen N, Andresen BS, Hougaard DM, Dunø M, Olsen RKJ. Use of Molecular Genetic Analyses in Danish Routine Newborn Screening. Int J Neonatal Screen 2021; 7:ijns7030050. [PMID: 34449524 PMCID: PMC8395600 DOI: 10.3390/ijns7030050] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 12/20/2022] Open
Abstract
Historically, the analyses used for newborn screening (NBS) were biochemical, but increasingly, molecular genetic analyses are being introduced in the workflow. We describe the application of molecular genetic analyses in the Danish NBS programme and show that second-tier molecular genetic testing is useful to reduce the false positive rate while simultaneously providing information about the precise molecular genetic variant and thus informing therapeutic strategy and easing providing information to parents. When molecular genetic analyses are applied as second-tier testing, valuable functional data from biochemical methods are available and in our view, such targeted NGS technology should be implemented when possible in the NBS workflow. First-tier NGS technology may be a promising future possibility for disorders without a reliable biomarker and as a general approach to increase the adaptability of NBS for a broader range of genetic diseases, which is important in the current landscape of quickly evolving new therapeutic possibilities. However, studies on feasibility, sensitivity, and specificity are needed as well as more insight into what views the general population has towards using genetic analyses in NBS. This may be sensitive to some and could have potentially negative consequences for the NBS programme.
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Affiliation(s)
- Allan Meldgaard Lund
- Center for Inherited Metabolic Disorders, Departments of Clinical Genetics and Pediatrics, Copenhagen University Hospital, 2100 Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Correspondence: ; Fax: +45-35454072
| | - Flemming Wibrand
- Metabolic Laboratory, Department of Clinical Genetics, Copenhagen University Hospital, 2100 Copenhagen, Denmark;
| | - Kristin Skogstrand
- Center for Neonatal Screening, Department for Congenital Disorders, Statens Serum Institute, 2300 Copenhagen, Denmark; (K.S.); (M.B.-H.); (D.M.H.)
| | - Marie Bækvad-Hansen
- Center for Neonatal Screening, Department for Congenital Disorders, Statens Serum Institute, 2300 Copenhagen, Denmark; (K.S.); (M.B.-H.); (D.M.H.)
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark; (N.G.); (R.K.J.O.)
| | - Brage Storstein Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark;
| | - David M. Hougaard
- Center for Neonatal Screening, Department for Congenital Disorders, Statens Serum Institute, 2300 Copenhagen, Denmark; (K.S.); (M.B.-H.); (D.M.H.)
| | - Morten Dunø
- Molecular Genetics Laboratory, Department of Clinical Genetics, Copenhagen University Hospital, 2100 Copenhagen, Denmark;
| | - Rikke Katrine Jentoft Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark; (N.G.); (R.K.J.O.)
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11
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New ratio as a useful marker for early diagnosis of proximal urea cycle disorders. Clin Chim Acta 2021; 520:154-159. [PMID: 34116006 DOI: 10.1016/j.cca.2021.06.011] [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: 05/10/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND AIMS Proximal urea cycle disorders (PUCDs) are not included in most newborn screening programs due to the lack of adequate markers to monitor. Failure to alter citrulline and glutamine levels, the prognostic markers commonly used, can results in high false negative. Therefore, new biomarkers, prognostic of PUCDs, are strongly desirable. MATERIALS AND METHODS We used tandem mass spectrometry to analyze blood spot from PUCDs patients during their follow up in our referral center focusing on glutamine to glutamate (Gln/Glu) ratio. We reanalyzed the same specimens of three patients after two months and the specimen of a new patient with suspicious of PUCD disorder. RESULTS Specimens of our patients shown a significant elevation of the ratio Gln/Glu compared to that of a healthy population (p < 0.05) as well as the specimens analyzed after two months, while the glutamine concentration dropped. New patient, showing high value of the ratio, was molecularly confirmed as PUCD patient. We further analyzed the blood spots from a neonatal population in order to fix a cut-off value and include it in a newborn screening panel. CONCLUSION Our preliminary results suggest that the Gln/Glu ratio could be a very useful diagnostic marker, more stable over time than glutamine, which could improve the performance in early PUCDs identification.
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