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Gaikwad S, Ganvir S, Uke P. Newborn Screening in Developing Countries: The Need of the Hour. Cureus 2024; 16:e59572. [PMID: 38832201 PMCID: PMC11144574 DOI: 10.7759/cureus.59572] [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: 01/25/2024] [Accepted: 05/03/2024] [Indexed: 06/05/2024] Open
Abstract
Screening newborns is recognized as an important health policy. It is cost-effective and is implemented as a national health program in most developed countries. Though births in developing countries contribute to more than half of the total births globally, newborn screening (NBS) is not yet implemented in most developing countries. If not diagnosed and treated timely, some of these infants will contribute to neonatal mortality. In contrast, others will have long-term sequelae like developmental delay, learning disabilities, behavioral abnormalities, and backward academic performance in the future. In addition, the diagnosis, management, and treatment of these conditions also carry a significant financial as well as emotional burden on the family. An NBS program can be the most rational and effective way to prevent such morbidities and mortalities. NBS in developing countries competes with other health issues such as the control of infectious diseases, vaccinations, and poor nutrition. Also, lack of government support, poor economy, inadequate public health education, lack of awareness among health care workers, early discharge from hospital, and many births out of hospital are the significant obstacles in the countries that lack total coverage. It is high time now to change our attitude; our focus should be not only on the reduction of mortality and infectious morbidity but also on reducing disabilities with the introduction of screening for newborns. Integrating NBS with the national healthcare system is crucial for successful implementation in developing countries. Integration should also include a payment scheme to reduce the economic burden on families. In recent years, many developing countries have started implementing pilot projects as a step toward the national program of screening newborns.
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Affiliation(s)
- Sarika Gaikwad
- Department of Pediatrics, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Shubhangi Ganvir
- Department of Pediatrics, Grant Medical College and Sir Jamshedjee Jeejeebhoy Group of Hospitals, Mumbai, IND
| | - Punam Uke
- Department of Pediatrics, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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2
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Leandro J, Houten SM. The lysine degradation pathway: Subcellular compartmentalization and enzyme deficiencies. Mol Genet Metab 2020; 131:14-22. [PMID: 32768327 DOI: 10.1016/j.ymgme.2020.07.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 02/07/2023]
Abstract
Lysine degradation via formation of saccharopine is a pathway confined to the mitochondria. The second pathway for lysine degradation, the pipecolic acid pathway, is not yet fully elucidated and known enzymes are localized in the mitochondria, cytosol and peroxisome. The tissue-specific roles of these two pathways are still under investigation. The lysine degradation pathway is clinically relevant due to the occurrence of two severe neurometabolic disorders, pyridoxine-dependent epilepsy (PDE) and glutaric aciduria type 1 (GA1). The existence of three other disorders affecting lysine degradation without apparent clinical consequences opens up the possibility to find alternative therapeutic strategies for PDE and GA1 through pathway modulation. A better understanding of the mechanisms, compartmentalization and interplay between the different enzymes and metabolites involved in lysine degradation is of utmost importance.
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Affiliation(s)
- João Leandro
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sander M Houten
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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3
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Baruteau J, Diez-Fernandez C, Lerner S, Ranucci G, Gissen P, Dionisi-Vici C, Nagamani S, Erez A, Häberle J. Argininosuccinic aciduria: Recent pathophysiological insights and therapeutic prospects. J Inherit Metab Dis 2019; 42:1147-1161. [PMID: 30723942 DOI: 10.1002/jimd.12047] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 12/20/2018] [Indexed: 12/30/2022]
Abstract
The first patients affected by argininosuccinic aciduria (ASA) were reported 60 years ago. The clinical presentation was initially described as similar to other urea cycle defects, but increasing evidence has shown overtime an atypical systemic phenotype with a paradoxical observation, that is, a higher rate of neurological complications contrasting with a lower rate of hyperammonaemic episodes. The disappointing long-term clinical outcomes of many of the patients have challenged the current standard of care and therapeutic strategy, which aims to normalize plasma ammonia and arginine levels. Interrogations have raised about the benefit of newborn screening or liver transplantation on the neurological phenotype. Over the last decade, novel discoveries enabled by the generation of new transgenic argininosuccinate lyase (ASL)-deficient mouse models have been achieved, such as, a better understanding of ASL and its close interaction with nitric oxide metabolism, ASL physiological role outside the liver, and the pathophysiological role of oxidative/nitrosative stress or excessive arginine treatment. Here, we present a collaborative review, which highlights these recent discoveries and novel emerging concepts about ASL role in human physiology, ASA clinical phenotype and geographic prevalence, limits of current standard of care and newborn screening, pathophysiology of the disease, and emerging novel therapies. We propose recommendations for monitoring of ASA patients. Ongoing research aims to better understand the underlying pathogenic mechanisms of the systemic disease to design novel therapies.
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Affiliation(s)
- Julien Baruteau
- UCL Great Ormond Street Institute of Child Health, NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
- Metabolic Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Carmen Diez-Fernandez
- Division of Metabolism and Children Research Centre (CRC), University Children's Hospital, Zurich, Switzerland
| | - Shaul Lerner
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israël
| | - Giusy Ranucci
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Paul Gissen
- UCL Great Ormond Street Institute of Child Health, NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
- Metabolic Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Carlo Dionisi-Vici
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Sandesh Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Ayelet Erez
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israël
| | - Johannes Häberle
- Division of Metabolism and Children Research Centre (CRC), University Children's Hospital, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP) and Neuroscience Center Zurich (ZNZ), Zurich, Switzerland
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4
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Belanger AM, Przybylska M, Gefteas E, Furgerson M, Geller S, Kloss A, Cheng SH, Zhu Y, Yew NS. Inhibiting neutral amino acid transport for the treatment of phenylketonuria. JCI Insight 2018; 3:121762. [PMID: 30046012 DOI: 10.1172/jci.insight.121762] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/19/2018] [Indexed: 12/21/2022] Open
Abstract
The neuropathological effects of phenylketonuria (PKU) stem from the inability of the body to metabolize excess phenylalanine (Phe), resulting in accumulation of Phe in the blood and brain. Since the kidney normally reabsorbs circulating amino acids with high efficiency, we hypothesized that preventing the renal uptake of Phe might provide a disposal pathway that could lower systemic Phe levels. SLC6A19 is a neutral amino acid transporter responsible for absorption of the majority of free Phe in the small intestine and reuptake of Phe by renal proximal tubule cells. Transgenic KO mice lacking SLC6A19 have elevated levels of Phe and other amino acids in their urine but are otherwise healthy. Here, we crossed the Pahenu2 mouse model of PKU with the Slc6a19-KO mouse. These mutant/KO mice exhibited abundant excretion of Phe in the urine and an approximately 70% decrease in plasma Phe levels. Importantly, brain Phe levels were decreased by 50%, and the levels of key neurotransmitters were increased in the mutant/KO mice. In addition, a deficit in spatial working memory and markers of neuropathology were corrected. Finally, treatment of Pahenu2 mice with Slc6a19 antisense oligonucleotides lowered Phe levels. The results suggest that inhibition of SLC6A19 may represent a novel approach for the treatment of PKU and related aminoacidopathies.
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MESH Headings
- Amines
- Amino Acid Transport Systems, Neutral/analysis
- Amino Acid Transport Systems, Neutral/genetics
- Amino Acid Transport Systems, Neutral/metabolism
- Amino Acids, Neutral/blood
- Amino Acids, Neutral/metabolism
- Animals
- Astrocytes/metabolism
- Astrocytes/pathology
- Biological Transport/drug effects
- Brain/metabolism
- Disease Models, Animal
- Female
- Gene Expression Regulation
- Genetic Diseases, Inborn/therapy
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Male
- Memory, Short-Term
- Mice
- Mice, Knockout
- Morpholinos/pharmacology
- Oligonucleotides/pharmacology
- Phenylalanine/blood
- Phenylalanine/metabolism
- Phenylketonurias/pathology
- Phenylketonurias/therapy
- Renal Reabsorption/drug effects
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5
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Nemeria NS, Gerfen G, Yang L, Zhang X, Jordan F. Evidence for functional and regulatory cross-talk between the tricarboxylic acid cycle 2-oxoglutarate dehydrogenase complex and 2-oxoadipate dehydrogenase on the l-lysine, l-hydroxylysine and l-tryptophan degradation pathways from studies in vitro. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:932-939. [PMID: 29752936 DOI: 10.1016/j.bbabio.2018.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 12/22/2022]
Abstract
Herein are reported findings in vitro suggesting both functional and regulatory cross-talk between the human 2-oxoglutarate dehydrogenase complex (hOGDHc), a key regulatory enzyme within the tricarboxylic acid cycle (TCA cycle), and a novel 2-oxoadipate dehydrogenase complex (hOADHc) from the final degradation pathway of l-lysine, l-hydroxylysine and l-tryptophan. The following could be concluded from our studies by using hOGDHc and hOADHc assembled from their individually expressed components in vitro: (i) Different substrate preferences (kcat/Km) were displayed by the two complexes even though they share the same dihydrolipoyl succinyltransferase (hE2o) and dihydrolipoyl dehydrogenase (hE3) components; (ii) Different binding modes were in evidence for the binary hE1o-hE2o and hE1a-hE2o subcomplexes according to fluorescence titrations using site-specifically labeled hE2o-derived proteins; (iii) Similarly to hE1o, the hE1a also forms the ThDP-enamine radical from 2-oxoadipate (electron paramagnetic resonance detection) in the oxidative half reaction; (iv) Both complexes produced superoxide/H2O2 from O2 in the reductive half reaction suggesting that hE1o, and hE1a (within their complexes) could both be sources of reactive oxygen species generation in mitochondria from 2-oxoglutarate and 2-oxoadipate, respectively; (v) Based on our findings, we speculate that hE2o can serve as a trans-glutarylase, in addition to being a trans-succinylase, a role suggested by others; (vi) The glutaryl-CoA produced by hOADHc inhibits hE1o, as does succinyl-CoA, suggesting a regulatory cross-talk between the two complexes on the different metabolic pathways.
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Affiliation(s)
- Natalia S Nemeria
- Department of Chemistry, Rutgers University, Newark, NJ 07102-1811, USA.
| | - Gary Gerfen
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY 10641-2304, USA
| | - Luying Yang
- Department of Chemistry, Rutgers University, Newark, NJ 07102-1811, USA
| | - Xu Zhang
- Department of Chemistry, Rutgers University, Newark, NJ 07102-1811, USA
| | - Frank Jordan
- Department of Chemistry, Rutgers University, Newark, NJ 07102-1811, USA.
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6
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α-Ketoadipic Acid and α-Aminoadipic Acid Cause Disturbance of Glutamatergic Neurotransmission and Induction of Oxidative Stress In Vitro in Brain of Adolescent Rats. Neurotox Res 2017; 32:276-290. [DOI: 10.1007/s12640-017-9735-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/30/2017] [Accepted: 04/05/2017] [Indexed: 12/21/2022]
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7
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Role of Cystathionine Gamma-Lyase in Immediate Renal Impairment and Inflammatory Response in Acute Ischemic Kidney Injury. Sci Rep 2016; 6:27517. [PMID: 27273292 PMCID: PMC4897642 DOI: 10.1038/srep27517] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 05/20/2016] [Indexed: 12/12/2022] Open
Abstract
Hydrogen sulfide (H2S) is known to act protectively during renal ischemia/reperfusion injury (IRI). However, the role of the endogenous H2S in acute kidney injury (AKI) is largely unclear. Here, we analyzed the role of cystathionine gamma-lyase (CTH) in acute renal IRI using CTH-deficient (Cth−/−) mice whose renal H2S levels were approximately 50% of control (wild-type) mice. Although levels of serum creatinine and renal expression of AKI marker proteins were equivalent between Cth−/− and control mice, histological analysis revealed that IRI caused less renal tubular damage in Cth−/− mice. Flow cytometric analysis revealed that renal population of infiltrated granulocytes/macrophages was equivalent in these mice. However, renal expression levels of certain inflammatory cytokines/adhesion molecules believed to play a role in IRI were found to be lower after IRI only in Cth−/− mice. Our results indicate that the systemic CTH loss does not deteriorate but rather ameliorates the immediate AKI outcome probably due to reduced inflammatory responses in the kidney. The renal expression of CTH and other H2S-producing enzymes was markedly suppressed after IRI, which could be an integrated adaptive response for renal cell protection.
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8
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Hagen J, te Brinke H, Wanders RJA, Knegt AC, Oussoren E, Hoogeboom AJM, Ruijter GJG, Becker D, Schwab KO, Franke I, Duran M, Waterham HR, Sass JO, Houten SM. Genetic basis of alpha-aminoadipic and alpha-ketoadipic aciduria. J Inherit Metab Dis 2015; 38:873-9. [PMID: 25860818 DOI: 10.1007/s10545-015-9841-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/12/2015] [Accepted: 03/16/2015] [Indexed: 10/23/2022]
Abstract
Alpha-aminoadipic and alpha-ketoadipic aciduria is an autosomal recessive inborn error of lysine, hydroxylysine, and tryptophan degradation. To date, DHTKD1 mutations have been reported in two alpha-aminoadipic and alpha-ketoadipic aciduria patients. We have now sequenced DHTKD1 in nine patients diagnosed with alpha-aminoadipic and alpha-ketoadipic aciduria as well as one patient with isolated alpha-aminoadipic aciduria, and identified causal mutations in eight. We report nine novel mutations, including three missense mutations, two nonsense mutations, two splice donor mutations, one duplication, and one deletion and insertion. Two missense mutations, one of which was reported before, were observed in the majority of cases. The clinical presentation of this group of patients was inhomogeneous. Our results confirm that alpha-aminoadipic and alpha-ketoadipic aciduria is caused by mutations in DHTKD1, and further establish that DHTKD1 encodes the E1 subunit of the alpha-ketoadipic acid dehydrogenase complex.
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Affiliation(s)
- Jacob Hagen
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, Box 1498, New York, NY, 10029, USA
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9
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New Cases of DHTKD1 Mutations in Patients with 2-Ketoadipic Aciduria. JIMD Rep 2015; 25:15-19. [PMID: 26141459 DOI: 10.1007/8904_2015_462] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/11/2015] [Accepted: 05/17/2015] [Indexed: 12/12/2022] Open
Abstract
2-Ketoadipic aciduria (OMIM 204750), a defect in the catabolic pathway of tryptophan, lysine, and hydroxylysine, is characterized by elevations in 2-ketoadipic, 2-aminoadipic, and 2-hydroxyadipic acids. Patients with the aforementioned biochemical profile have been described with a wide range of clinical presentations, from early-onset developmental delay, epilepsy, ataxia, and microcephaly to completely normal. This broad range of phenotypes has led some to question whether 2-ketoadipic aciduria represents a true disease state or if the biochemical abnormalities found in these patients merely reflect an ascertainment bias. We present four additional individuals from two families, with 2-ketoadipic aciduria with compound heterozygous or homozygous mutations in DHTKD1, three of which remain asymptomatic.
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10
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Hagiya Y, Kamata S, Mitsuoka S, Okada N, Yoshida S, Yamamoto J, Ohkubo R, Abiko Y, Yamada H, Akahoshi N, Kasahara T, Kumagai Y, Ishii I. Hemizygosity of transsulfuration genes confers increased vulnerability against acetaminophen-induced hepatotoxicity in mice. Toxicol Appl Pharmacol 2014; 282:195-206. [PMID: 25499718 DOI: 10.1016/j.taap.2014.11.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 12/27/2022]
Abstract
The key mechanism for acetaminophen hepatotoxicity is cytochrome P450 (CYP)-dependent formation of N-acetyl-p-benzoquinone imine, a potent electrophile that forms protein adducts. Previous studies revealed the fundamental role of glutathione, which binds to and detoxifies N-acetyl-p-benzoquinone imine. Glutathione is synthesized from cysteine in the liver, and N-acetylcysteine is used as a sole antidote for acetaminophen poisoning. Here, we evaluated the potential roles of transsulfuration enzymes essential for cysteine biosynthesis, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH), in acetaminophen hepatotoxicity using hemizygous (Cbs(+/-) or Cth(+/-)) and homozygous (Cth(-/-)) knockout mice. At 4 h after intraperitoneal acetaminophen injection, serum alanine aminotransferase levels were highly elevated in Cth(-/-) mice at 150 mg/kg dose, and also in Cbs(+/-) or Cth(+/-) mice at 250 mg/kg dose, which was associated with characteristic centrilobular hepatocyte oncosis. Hepatic glutathione was depleted while serum malondialdehyde accumulated in acetaminophen-injected Cth(-/-) mice but not wild-type mice, although glutamate-cysteine ligase (composed of catalytic [GCLC] and modifier [GCLM] subunits) became more activated in the livers of Cth(-/-) mice with lower Km values for Cys and Glu. Proteome analysis using fluorescent two-dimensional difference gel electrophoresis revealed 47 differentially expressed proteins after injection of 150 mg acetaminophen/kg into Cth(-/-) mice; the profiles were similar to 1000 mg acetaminophen/kg-treated wild-type mice. The prevalence of Cbs or Cth hemizygosity is estimated to be 1:200-300 population; therefore, the deletion or polymorphism of either transsulfuration gene may underlie idiosyncratic acetaminophen vulnerability along with the differences in Cyp, Gclc, and Gclm gene activities.
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Affiliation(s)
- Yoshifumi Hagiya
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Shotaro Kamata
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Saya Mitsuoka
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Norihiko Okada
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Saori Yoshida
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Junya Yamamoto
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Rika Ohkubo
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Yumi Abiko
- Environmental Biology Laboratory, School of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan
| | - Hidenori Yamada
- Jobu Hospital for Respiratory Diseases, Maebashi 371-0048, Japan
| | - Noriyuki Akahoshi
- Department of Immunology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Tadashi Kasahara
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan
| | - Yoshito Kumagai
- Environmental Biology Laboratory, School of Medicine, University of Tsukuba, Ibaraki 305-8575, Japan
| | - Isao Ishii
- Department of Biochemistry, Keio University School of Pharmaceutical Sciences, Tokyo 105-8512, Japan.
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11
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Mak CM, Lee HCH, Chan AYW, Lam CW. Inborn errors of metabolism and expanded newborn screening: review and update. Crit Rev Clin Lab Sci 2014; 50:142-62. [PMID: 24295058 DOI: 10.3109/10408363.2013.847896] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Inborn errors of metabolism (IEM) are a phenotypically and genetically heterogeneous group of disorders caused by a defect in a metabolic pathway, leading to malfunctioning metabolism and/or the accumulation of toxic intermediate metabolites. To date, more than 1000 different IEM have been identified. While individually rare, the cumulative incidence has been shown to be upwards of 1 in 800. Clinical presentations are protean, complicating diagnostic pathways. IEM are present in all ethnic groups and across every age. Some IEM are amenable to treatment, with promising outcomes. However, high clinical suspicion alone is not sufficient to reduce morbidities and mortalities. In the last decade, due to the advent of tandem mass spectrometry, expanded newborn screening (NBS) has become a mandatory public health strategy in most developed and developing countries. The technology allows inexpensive simultaneous detection of more than 30 different metabolic disorders in one single blood spot specimen at a cost of about USD 10 per baby, with commendable analytical accuracy and precision. The sensitivity and specificity of this method can be up to 99% and 99.995%, respectively, for most amino acid disorders, organic acidemias, and fatty acid oxidation defects. Cost-effectiveness studies have confirmed that the savings achieved through the use of expanded NBS programs are significantly greater than the costs of implementation. The adverse effects of false positive results are negligible in view of the economic health benefits generated by expanded NBS and these could be minimized through increased education, better communication, and improved technologies. Local screening agencies should be given the autonomy to develop their screening programs in order to keep pace with international advancements. The development of biochemical genetics is closely linked with expanded NBS. With ongoing advancements in nanotechnology and molecular genomics, the field of biochemical genetics is still expanding rapidly. The potential of tandem mass spectrometry is extending to cover more disorders. Indeed, the use of genetic markers in T-cell receptor excision circles for severe combined immunodeficiency is one promising example. NBS represents the highest volume of genetic testing. It is more than a test and it warrants systematic healthcare service delivery across the pre-analytical, analytical, and post-analytical phases. There should be a comprehensive reporting system entailing genetic counselling as well as short-term and long-term follow-up. It is essential to integrate existing clinical IEM services with the expanded NBS program to enable close communication between the laboratory, clinicians, and allied health parties. In this review, we will discuss the history of IEM, its clinical presentations in children and adult patients, and its incidence among different ethnicities; the history and recent expansion of NBS, its cost-effectiveness, associated pros and cons, and the ethical issues that can arise; the analytical aspects of tandem mass spectrometry and post-analytical perspectives regarding result interpretation.
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Affiliation(s)
- Chloe Miu Mak
- Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital , Hong Kong, SAR , China and
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12
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Balmer C, Pandey AV, Rüfenacht V, Nuoffer JM, Fang P, Wong LJ, Häberle J. Mutations and Polymorphisms in the HumanArgininosuccinate Lyase(ASL) Gene. Hum Mutat 2013; 35:27-35. [DOI: 10.1002/humu.22469] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 10/09/2013] [Indexed: 12/30/2022]
Affiliation(s)
- Cécile Balmer
- Division of Metabolism; University Children's Hospital; Zurich Switzerland
- Children's Research Center; Zurich Switzerland
| | - Amit V. Pandey
- Pediatric Endocrinology; Departments of Pediatrics and Clinical Research; University of Bern; Bern Switzerland
| | - Véronique Rüfenacht
- Division of Metabolism; University Children's Hospital; Zurich Switzerland
- Children's Research Center; Zurich Switzerland
| | - Jean-Marc Nuoffer
- University Institute of Clinical Chemistry; University Children's Hospital; University of Bern; Bern 3010 Switzerland
| | - Ping Fang
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston Texas 77030
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston Texas 77030
| | - Johannes Häberle
- Division of Metabolism; University Children's Hospital; Zurich Switzerland
- Children's Research Center; Zurich Switzerland
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13
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Abstract
Amino acids are essential building blocks of all mammalian cells. In addition to their role in protein synthesis, amino acids play an important role as energy fuels, precursors for a variety of metabolites and as signalling molecules. Disorders associated with the malfunction of amino acid transporters reflect the variety of roles that they fulfil in human physiology. Mutations of brain amino acid transporters affect neuronal excitability. Mutations of renal and intestinal amino acid transporters affect whole-body homoeostasis, resulting in malabsorption and renal problems. Amino acid transporters that are integral parts of metabolic pathways reduce the function of these pathways. Finally, amino acid uptake is essential for cell growth, thereby explaining their role in tumour progression. The present review summarizes the involvement of amino acid transporters in these roles as illustrated by diseases resulting from transporter malfunction.
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14
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Renal imino acid and glycine transport system ontogeny and involvement in developmental iminoglycinuria. Biochem J 2010; 428:397-407. [DOI: 10.1042/bj20091667] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Renal maturation occurs post-natally in many species and reabsorption capacity at birth can vary substantially from the mature kidney. However, little is known regarding the maturation of amino acid transport mechanisms, despite the well-known physiological state of developmental iminoglycinuria. Commonly seen during early infancy, developmental iminoglycinuria is a transient version of the persistent inherited form of the disorder, referred to as iminoglycinuria, and manifests as a urinary hyperexcretion of proline, hydroxyproline and glycine. The transporters involved in developmental iminoglycinuria and their involvement in the improvement of renal reabsorption capacity remain unknown. qPCR (quantitative real-time PCR) and Western blot analysis in developing mouse kidney revealed that the expression of Slc6a18, Slc6a19, Slc6a20a and Slc36a2 was lower at birth (approx. 3.4-, 5.0-, 2.4- and 3.0-fold less than adult kidney by qPCR respectively) and increased during development. Furthermore, immunofluorescence confocal microscopy demonstrated the absence of apical expression of Slc6a18, Slc6a19, Slc6a20a and the auxiliary protein collectrin in kidneys of mice at birth. This correlated with the detection of iminoglycinuria during the first week of life. Iminoglycinuria subsided (proline reduction preceded glycine) in the second week of life, which correlated with an increase in the expression of Slc6a19 and Slc6a20a. Mice achieved an adult imino acid and glycine excretion profile by the fourth week, at which time the expression level of all transporters was comparable with adult mice. In conclusion, these results demonstrate the delayed expression and maturation of Slc6a18, Slc6a19, Slc6a20a and Slc36a2 in neonatal mice and thus the molecular mechanism of developmental iminoglycinuria.
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15
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Cheon CK, Lee BH, Ko JM, Kim HJ, Yoo HW. Novel mutation in SLC6A19 causing late-onset seizures in Hartnup disorder. Pediatr Neurol 2010; 42:369-71. [PMID: 20399395 DOI: 10.1016/j.pediatrneurol.2010.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 12/04/2009] [Accepted: 01/04/2010] [Indexed: 10/19/2022]
Abstract
Hartnup disorder is caused by an inborn error of neutral amino acid transport in the kidneys and intestines. It is characterized by pellagra-like rash, ataxia, and psychotic behavior. Elevated urinary neutral amino acids are the first indicator of the disorder. SLC6A19 was identified as the causative gene in autosomal-recessive Hartnup disorder, which encodes the amino acid transporter B(0)AT1, mediating neutral amino acid transport from the luminal compartment to the intracellular space. Here, we report on a Korean boy aged 8 years and 5 months with Hartnup disorder, as confirmed by SLC6A19 gene analysis. He manifested seizures, attention-deficit hyperactivity disorder, and mental retardation without pellagra or ataxia. Multiple neutral amino acids were increased in his urine, and genetic analysis of SLC6A19 revealed compound heterozygous mutations, c.908C>T (p.Ser303Leu) and c.1787_1788insG (p.Thr596fsX73), both of which are novel. A novel SLC6A19 gene mutation was associated with late-onset seizures in a Korean patient with Hartnup disorder.
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Affiliation(s)
- Chong Kun Cheon
- Department of Pediatrics, Genetic and Metabolic Clinic, Children's Hospital, Pusan National University, Gyeongnam, South Korea
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16
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Mercimek-Mahmutoglu S, Moeslinger D, Häberle J, Engel K, Herle M, Strobl MW, Scheibenreiter S, Muehl A, Stöckler-Ipsiroglu S. Long-term outcome of patients with argininosuccinate lyase deficiency diagnosed by newborn screening in Austria. Mol Genet Metab 2010; 100:24-8. [PMID: 20236848 DOI: 10.1016/j.ymgme.2010.01.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Accepted: 01/24/2010] [Indexed: 11/16/2022]
Abstract
Twenty-three patients with late onset argininosuccinate lyase deficiency (ASLD) were identified during a 27-year period of newborn screening in Austria (1:95,600, 95% CI=1:68,036-1:162,531). One additional patient was identified outside the newborn screening with neonatal hyperammonemia. Long-term outcome data were available in 17 patients (median age 13 years) ascertained by newborn screening. Patients were treated with protein restricted diet and oral arginine supplementation during infancy and childhood. IQ was average/above average in 11 (65%), low average in 5 (29%), and in the mild intellectual disability range in 1 (6%) patients. Four patients had an abnormal EEG without evidence of clinical seizures and three had abnormal liver function tests and/or evidence of hepatic steatosis. Plasma citrulline levels were elevated in four patients. Plasma ammonia levels were within normal range prior and after a protein load in all patients. Seven different mutations were identified in the 16 alleles investigated. Four mutations were novel (p.E189G, p.R168C, p.R126P, and p.D423H). All mutations were associated with low argininosuccinate lyase activities (0-15%) in red blood cells. Newborn screening might be beneficial in the prevention of chronic neurologic and intellectual sequelae in late onset ASLD, but a proportion of benign variants might have contributed to the overall favorable outcome as well.
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Affiliation(s)
- S Mercimek-Mahmutoglu
- Department of Pediatrics, Division of Biochemical Diseases, British Columbia University, Vancouver, BC, Canada
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17
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Bröer S, Bailey CG, Kowalczuk S, Ng C, Vanslambrouck JM, Rodgers H, Auray-Blais C, Cavanaugh JA, Bröer A, Rasko JEJ. Iminoglycinuria and hyperglycinuria are discrete human phenotypes resulting from complex mutations in proline and glycine transporters. J Clin Invest 2008. [PMID: 19033659 DOI: 10.1172/jci3662536625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023] Open
Abstract
Iminoglycinuria (IG) is an autosomal recessive abnormality of renal transport of glycine and the imino acids proline and hydroxyproline, but the specific genetic defect(s) have not been determined. Similarly, although the related disorder hyperglycinuria (HG) without iminoaciduria has been attributed to heterozygosity of a putative defective glycine, proline, and hydroxyproline transporter, confirming the underlying genetic defect(s) has been difficult. Here we applied a candidate gene sequencing approach in 7 families first identified through newborn IG screening programs. Both inheritance and functional studies identified the gene encoding the proton amino acid transporter SLC36A2 (PAT2) as the major gene responsible for IG in these families, and its inheritance was consistent with a classical semidominant pattern in which 2 inherited nonfunctional alleles conferred the IG phenotype, while 1 nonfunctional allele was sufficient to confer the HG phenotype. Mutations in SLC36A2 that retained residual transport activity resulted in the IG phenotype when combined with mutations in the gene encoding the imino acid transporter SLC6A20 (IMINO). Additional mutations were identified in the genes encoding the putative glycine transporter SLC6A18 (XT2) and the neutral amino acid transporter SLC6A19 (B0AT1) in families with either IG or HG, suggesting that mutations in the genes encoding these transporters may also contribute to these phenotypes. In summary, although recognized as apparently simple Mendelian disorders, IG and HG exhibit complex molecular explanations depending on a major gene and accompanying modifier genes.
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Affiliation(s)
- Stefan Bröer
- School of Biochemistry and Molecular Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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18
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Bröer S, Bailey CG, Kowalczuk S, Ng C, Vanslambrouck JM, Rodgers H, Auray-Blais C, Cavanaugh JA, Bröer A, Rasko JEJ. Iminoglycinuria and hyperglycinuria are discrete human phenotypes resulting from complex mutations in proline and glycine transporters. J Clin Invest 2008; 118:3881-92. [PMID: 19033659 DOI: 10.1172/jci36625] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 10/01/2008] [Indexed: 11/17/2022] Open
Abstract
Iminoglycinuria (IG) is an autosomal recessive abnormality of renal transport of glycine and the imino acids proline and hydroxyproline, but the specific genetic defect(s) have not been determined. Similarly, although the related disorder hyperglycinuria (HG) without iminoaciduria has been attributed to heterozygosity of a putative defective glycine, proline, and hydroxyproline transporter, confirming the underlying genetic defect(s) has been difficult. Here we applied a candidate gene sequencing approach in 7 families first identified through newborn IG screening programs. Both inheritance and functional studies identified the gene encoding the proton amino acid transporter SLC36A2 (PAT2) as the major gene responsible for IG in these families, and its inheritance was consistent with a classical semidominant pattern in which 2 inherited nonfunctional alleles conferred the IG phenotype, while 1 nonfunctional allele was sufficient to confer the HG phenotype. Mutations in SLC36A2 that retained residual transport activity resulted in the IG phenotype when combined with mutations in the gene encoding the imino acid transporter SLC6A20 (IMINO). Additional mutations were identified in the genes encoding the putative glycine transporter SLC6A18 (XT2) and the neutral amino acid transporter SLC6A19 (B0AT1) in families with either IG or HG, suggesting that mutations in the genes encoding these transporters may also contribute to these phenotypes. In summary, although recognized as apparently simple Mendelian disorders, IG and HG exhibit complex molecular explanations depending on a major gene and accompanying modifier genes.
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Affiliation(s)
- Stefan Bröer
- School of Biochemistry and Molecular Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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19
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Waisbren SE, Levy HL, Noble M, Matern D, Gregersen N, Pasley K, Marsden D. Short-chain acyl-CoA dehydrogenase (SCAD) deficiency: an examination of the medical and neurodevelopmental characteristics of 14 cases identified through newborn screening or clinical symptoms. Mol Genet Metab 2008; 95:39-45. [PMID: 18676165 PMCID: PMC4204643 DOI: 10.1016/j.ymgme.2008.06.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 06/10/2008] [Indexed: 12/27/2022]
Abstract
The medical and neurodevelopmental characteristics of 14 children with short-chain acyl-CoA dehydrogenase deficiency (SCADD) are described. Eight were detected as neonates by newborn screening. Three children diagnosed on the basis of clinical symptoms had normal newborn screening results while three were born in states that did not screen for SCADD. Treatment included frequent feedings and a low fat diet. All children identified by newborn screening demonstrated medical and neuropsychological development within the normative range on follow-up, although one child had a relative weakness in the motor area and another child exhibited mild speech delay. Of the three clinically identified children with newborn screening results below the cut-off value, two were healthy and performed within the normal range on cognitive and motor tests at follow-up. Four clinically identified children with SCADD experienced persistent symptoms and/or developmental delay. However, in each of these cases, there were supplementary or alternative explanations for medical and neuropsychological deficits. Results indicated no genotype-phenotype correlations. These findings suggest that SCADD might be benign and the clinical symptoms ascribed to SCADD reflective of ascertainment bias or that early identification and treatment prevented complications that may have occurred due to interaction between genetic susceptibility and other genetic factors or environmental stressors.
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Affiliation(s)
- S E Waisbren
- Department of Genetics, Children's Hospital Boston, Harvard Medical School, Boston, MA 02215, USA.
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20
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Azmanov DN, Rodgers H, Auray-Blais C, Giguère R, Bailey C, Bröer S, Rasko JEJ, Cavanaugh JA. Persistence of the Common Hartnup Disease D173N Allele in Populations of European Origin. Ann Hum Genet 2007; 71:755-61. [PMID: 17555458 DOI: 10.1111/j.1469-1809.2007.00375.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hartnup disorder is an aminoaciduria that results from mutations in the recently described gene SLC6A19 on chromosome 5p15.33. The disease is inherited in a simple recessive manner and ten different mutations have been described to date. One mutation, the D173N allele, is present in 42% of Hartnup chromosomes from apparently unrelated families from both Australia and North America. We report an investigation of the origins of the D173N allele using a unique combination of variants including SNPs, microsatellites, and a VNTR across 211 Kb spanning the SLC6A19 locus. All individuals who carry the mutant allele share an identical core haplotype suggesting a single common ancestor, indicating that the elevated frequency of the D173N allele is not a result of recurrent mutation. Analyses of these data indicate that the allele is more than 1000 years old. We compare the reasons for survival of this allele with other major alleles in some other common autosomal recessive diseases occurring in European Caucasians. We postulate that survival of this allele may be a consequence of failure of the allele to completely inactivate the transport of neutral amino acids.
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Affiliation(s)
- Dimitar N Azmanov
- Medical Genetics Research Unit, ANU Medical School, Canberra, Australia
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21
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Padilla CD, Therrell BL. Newborn screening in the Asia Pacific region. J Inherit Metab Dis 2007; 30:490-506. [PMID: 17643195 DOI: 10.1007/s10545-007-0687-7] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 06/07/2007] [Accepted: 06/08/2007] [Indexed: 10/23/2022]
Abstract
The success of blood spot newborn screening in the USA led to early screening efforts in parts of the Asia Pacific Region in the mid-1960s. While there were early screening leaders in the region, many of the countries with depressed and developing economies are only now beginning organized screening efforts. Four periods of screening growth in the Asia Pacific region were identified. Beginning in the 1960s, blood spot screening began in New Zealand and Australia, followed by Japan and a cord blood screening programme for G6PD deficiency in Singapore. In the 1980s, established programmes added congenital hypothyroidism and new programmes developed in Taiwan, Hong Kong, China (Shanghai), India and Malaysia. Programmes developing in the 1990s built on the experience of others developing more rapidly in Korea, Thailand and the Philippines. In the 2000s, with limited funding support from the International Atomic Energy Agency, there has been screening programme development around detection of congenital hypothyroidism in Indonesia, Mongolia, Sri Lanka, Myanmar and Pakistan. Palau has recently contracted with the Philippine newborn screening programme. There is little information available on newborn screening activities in Nepal, Cambodia, Laos and the other Pacific Island nations, with no organized screening efforts apparent. Since approximately half of the births in the world occur in the Asia Pacific Region, it is important to continue the ongoing implementation and expansion efforts so that these children can attain the same health status as children in more developed parts of the world and their full potential can be realized.
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Affiliation(s)
- Carmencita D Padilla
- Department of Pediatrics, College of Medicine, and Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila, Philippines.
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22
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Tadiboyina VT, Rupar A, Atkison P, Feigenbaum A, Kronick J, Wang J, Hegele RA. Novel mutation in DGUOK in hepatocerebral mitochondrial DNA depletion syndrome associated with cystathioninuria. Am J Med Genet A 2005; 135:289-91. [PMID: 15887277 DOI: 10.1002/ajmg.a.30748] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mitochondrial depletion syndrome (MDS) refers to a heterogeneous group of mitochondrial disorders characterized by a reduction of the mtDNA copy number in affected tissues. Mutations in DGUOK encoding deoxyguanosine kinase (MIM 601465) cause the hepatocerebral form of MDS (MIM 251880). Cystathioninuria (MIM 219500) can result from mutations in CTH encoding cystathionine gamma lyase (MIM 607657) or can be a secondary finding in several diverse clinical conditions. We present three patients from two apparently unrelated old colony Mennonite families, each of whom had the hepatocerebral form of MDS together with cystathioninuria. Each affected child was homozygous for the novel DGUOK p.D255Y mutation, but had no CTH mutation, indicating that the hepatocerebral form of MDS might be associated with secondary cystathioninuria.
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Affiliation(s)
- Venu T Tadiboyina
- Robarts Research Institute and University of Western Ontario, London, Ontario, Canada
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23
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Seow HF, Bröer S, Bröer A, Bailey CG, Potter SJ, Cavanaugh JA, Rasko JEJ. Hartnup disorder is caused by mutations in the gene encoding the neutral amino acid transporter SLC6A19. Nat Genet 2004; 36:1003-7. [PMID: 15286788 DOI: 10.1038/ng1406] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Accepted: 06/28/2004] [Indexed: 11/09/2022]
Abstract
Hartnup disorder (OMIM 234500) is an autosomal recessive abnormality of renal and gastrointestinal neutral amino acid transport noted for its clinical variability. We localized a gene causing Hartnup disorder to chromosome 5p15.33 and cloned a new gene, SLC6A19, in this region. SLC6A19 is a sodium-dependent and chloride-independent neutral amino acid transporter, expressed predominately in kidney and intestine, with properties of system B(0). We identified six mutations in SLC6A19 that cosegregated with disease in the predicted recessive manner, with most affected individuals being compound heterozygotes. The disease-causing mutations that we tested reduced neutral amino acid transport function in vitro. Population frequencies for the most common mutated SLC6A19 alleles are 0.007 for 517G --> A and 0.001 for 718C --> T. Our findings indicate that SLC6A19 is the long-sought gene that is mutated in Hartnup disorder; its identification provides the opportunity to examine the inconsistent multisystemic features of this disorder.
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Affiliation(s)
- Heng F Seow
- Gene Therapy, Centenary Institute of Cancer Medicine & Cell Biology, University of Sydney, NSW 2042, Australia
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24
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Banta-Wright SA, Steiner RD. Tandem mass spectrometry in newborn screening: a primer for neonatal and perinatal nurses. J Perinat Neonatal Nurs 2004; 18:41-58; quiz 59-60. [PMID: 15027667 DOI: 10.1097/00005237-200401000-00005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Since 1961, newborn screening for errors of metabolism (EM) has improved the diagnosis, treatment and outcome of newborns with an EM. Recently, advances in laboratory technology with tandem mass spectrometry (MS/MS) has increased the identification of newborns with an EM. With a single dried filter paper blood spot (Guthrie R, Susi A. A simple phenylalanine method for detecting PKU in large populations of newborn infants. Pediatrics. 1963;32:338-343), MS/MS can identify more than 30 disorders of metabolism. This review will explore MS/MS to provide a better understanding of the development and application of this technology to newborn screening for perinatal and neonatal nurses.
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25
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Wang J, Hegele RA. Genomic basis of cystathioninuria (MIM 219500) revealed by multiple mutations in cystathionine gamma-lyase (CTH). Hum Genet 2003; 112:404-8. [PMID: 12574942 DOI: 10.1007/s00439-003-0906-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2002] [Accepted: 12/13/2002] [Indexed: 11/24/2022]
Abstract
Hereditary cystathioninuria (MIM 219500) is presumed to be caused by deficiency of the activity of cystathionine gamma-lyase (cystathionase; CTH EC 4.4.1.1), which is normally required for the conversion of methionine into cysteine. To date, no mutations have been described among patients with cystathioninuria. From genomic DNA, we sequenced CTH in four unrelated probands with cystathioninuria. We found two nonsense mutations, namely exon 8 c.940-941delCT and exon 11 c.1220delC, and two missense mutations, namely exon 2 c.356C>T (T67I) and exon 7 c.874C>G (Q240E). All affected subjects were either simple homozygotes or compound heterozygotes. A common non-synonymous single nucleotide polymorphism in exon 12, namely c.1364G>T (S403I), was also identified and characterized in four ethnic groups. The reagents described in this report make the molecular diagnosis of cystathioninuria possible, allowing for studies of phenotype-genotype correlation. Also, the availability of a common non-synonymous SNP can allow for testing of association of the CTH gene with biochemical traits affected by trans-sulfuration, such as plasma concentrations of homocysteine or even cystathionine itself, in addition to more downstream clinical phenotypes, such as vascular disease.
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Affiliation(s)
- Jian Wang
- Blackburn Cardiovascular Genetics Laboratory, Robarts Research Institute, 406-100 Perth Drive, London, Ontario, N6A 5K8, Canada
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26
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Potter SJ, Lu A, Wilcken B, Green K, Rasko JEJ. Hartnup disorder: polymorphisms identified in the neutral amino acid transporter SLC1A5. J Inherit Metab Dis 2002; 25:437-48. [PMID: 12555937 DOI: 10.1023/a:1021286714582] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hartnup disorder is an inborn error of renal and gastrointestinal neutral amino acid transport. The cloning and functional characterization of the 'system B0' neutral amino acid transporter SLC1A5 led to it being proposed as a candidate gene for Hartnup disorder. Linkage analysis performed at 19q13.3, the chromosomal position of SLC1A5, was suggestive of an association with the Hartnup phenotype in some families. However, SLC1A5 was not linked to the Hartnup phenotype in other families. Linkage analysis also excluded an alternative candidate region at 11q13 implicated by a putative mouse model for Hartnup disorder. Sequencing of the coding region of SLC1A5 in Hartnup patients revealed two coding region polymorphisms. These mutations did not alter the predicted amino acid sequence of SLC1A5 and were considered unlikely to play a role in Hartnup disorder. There were no mutations in splice sites flanking each exon. Quantitative RT-PCR of SLC1A5 messenger RNA in affected and unaffected subjects did not support systemic differences in expression as an explanation for Hartnup disorder. In the six unrelated Hartnup pedigrees studied, examination of linkage at 19q13.3, polymorphisms in the coding sequence and quantitation of expression of SLC1A5 did not suffice to explain the defect in neutral amino acid transport.
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Affiliation(s)
- S J Potter
- Gene Therapy Research Unit, Centenary Institute of Cancer Medicine and Cell Biology, NSW, Australia
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27
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Xia ZW, Inoue Y, Ohse M, Shinka T, Kuhara T. A study on α-ketoadipic aciduria by gas chromatographic-mass spectrometry. World J Gastroenterol 2000; 6:766-769. [PMID: 11819692 PMCID: PMC4688861 DOI: 10.3748/wjg.v6.i5.766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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28
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Zhang J, Zhang M, Sugahara K, Sagara Y, Spirito A, Kodama H. D-cystathionine ketimine and L-cystathionine ketimine enhance superoxide generation by human neutrophils in a different manner. Arch Biochem Biophys 1999; 363:55-9. [PMID: 10049498 DOI: 10.1006/abbi.1998.1063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of d-cystathionine ketimine (D-CK) and l-cystathionine ketimine (L-CK) on the stimulus-induced superoxide generation by human neutrophils were compared. When the cells were preincubated with D-CK, the superoxide generation induced by arachidonic acid (AA), phorbol 12-myristate 13-acetate (PMA), and N-formyl-methionyl-leucyl-phenylalanine (fMLP) were enhanced, showing a dependence on D-CK concentration. The rate of enhancement by D-CK was AA > PMA > fMLP. On the contrary, L-CK largely enhanced the fMLP-induced superoxide generation, whereas it showed no effect on those induced by AA and PMA. The superoxide generations induced by AA and PMA in the D-CK-treated cells were suppressed by staurosporine, while those in the L-CK-treated cells were not affected. Genistein suppressed the fMLP-induced superoxide generation in the L-CK-treated cells more efficiently than that in the D-CK-treated cells. D-CK enhanced seryl phosphorylation of 16. 5-kDa protein in human neutrophils, while L-CK enhanced tyrosyl phosphorylation of 45-kDa protein.
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Affiliation(s)
- J Zhang
- Department of Chemistry, Kochi Medical School, Kochi, Okocho, Nankoku, 783-8505, Japan
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29
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Affiliation(s)
- Harvey L Levy
- Children’s Hospital, 300 Longwood Avenue, IC-106, Boston, MA 02115, Fax 617-730-0461
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30
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Abstract
Hydroxyproline is a major constituent of collagen. It accumulates as the free imino acid in a rarely reported inborn error of metabolism known as hydroxyprolinemia. This metabolic disorder was initially described in association with mental retardation, but subsequent identification in clinically normal individuals has led to the supposition that it is benign. The possibility that hydroxyprolinemia might have an adverse effect on cognitive development without producing mental retardation has not been determined nor has its incidence been reported. We prospectively studied a girl with untreated hydroxyprolinemia identified by routine neonatal urine screening, the only infant found among 1 million screened, and compared her with her unaffected dizygotic twin sister. Plasma and urine hydroxyproline were increased approximately 10-fold and 100-fold, respectively, in the affected twin. Both girls have had normal growth, with the affected twin taller than her sister. On neuropsychologic testing, the affected twin was within normal limits, performing slightly better than her sister on verbal and achievement tests but less well on visual perceptual testing. It appears that hydroxyprolinemia has caused no physical or general cognitive deficits. The possibility of an effect on visual perceptual functioning, although unlikely, cannot be eliminated.
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Affiliation(s)
- S Z Kim
- Division of Genetics, Children's Hospital, Boston, MA 02115, USA
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31
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Hammond JW, Potter M, Wilcken B, Truscott R. Siblings with gamma-glutamyltransferase deficiency. J Inherit Metab Dis 1995; 18:82-3. [PMID: 7623451 DOI: 10.1007/bf00711381] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- J W Hammond
- NSW Biochemical Genetics Service, Oliver Latham Laboratory, Royal Alexandra Hospital for Children, North Ryde, Sydney
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32
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Lemieux B, Auray-Blais C, Giguère R, Shapcott D, Scriver CR. Newborn urine screening experience with over one million infants in the Quebec Network of Genetic Medicine. J Inherit Metab Dis 1988; 11:45-55. [PMID: 3128688 DOI: 10.1007/bf01800056] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We screened urine for chemical individuality in over 1 million newborn infants, by various chromatographic (thin-layer), chemical and spectrophotometric methods, 12 procedures in all. The programme is part of the Quebec Network of Genetic Medicine. Voluntary urine screening began in 1971 and has evolved with changes in choice of tests and times of sample collection. Urine samples were collected on filter paper at either 5, 14 or 21 days after birth; results were best with the 21-day test. Compliance is over 94% with the latter and over 98% with requests for repeat samples. Screening is centralized in one laboratory; follow-up diagnosis, counselling and management are done at four regional centres. Incidence of phenotypes ranged from 1:4300 live births (for expressed cystinuria alleles) to 1 per million (for hyperargininaemia). Over 20 inherited Mendelian disorders were identified. 30 patients required aggressive medical management. We show how this programme can be used for neuroblastoma screening.
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Affiliation(s)
- B Lemieux
- Département de pédiatrie, Centre hospitalier universitaire de Sherbrooke, Québec, Canada
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33
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Mattingley JM. Paper chromatography of urinary amino acids. A 30 year survey of dietary influences on the normal pattern, and patients' results. Biomed Chromatogr 1986; 1:95-100. [PMID: 3506825 DOI: 10.1002/bmc.1130010302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In the clinical laboratory, paper chromatography is still the most useful, simple, inexpensive procedure for initial identification of abnormalities of amino acid excretion. The results of its use for more than 8000 paediatric and adult renal patients is surveyed. Nonspecific generalized aminoaciduria was the most frequent abnormality found, comprising some 70% of abnormal results, with cystine-lysinuria the next most common. The identification of the abnormal excretory pattern of amino acids as distinct from the normal was complicated by the effects of the New Zealand diet. In particular, valine, citrulline, hydroxyproline and glutamic acid are found in considerable amounts as part of the normal pattern. Their dietary origin is discussed. Varying mixtures of monosaccharides and disaccharides occurred in association with a range of amino acid patterns.
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Affiliation(s)
- J M Mattingley
- Department of Laboratory Services, Wellington Hospital, New Zealand
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Scriver CR, Clow CL, Reade TM, Goodyer P, Auray-Blais C, Giguère R, Lemieux B. Ontogeny modifies manifestations of cystinuria genes: implications for counseling. J Pediatr 1985; 106:411-6. [PMID: 3919167 DOI: 10.1016/s0022-3476(85)80666-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Among 339,868 newborn infants screened at 3 weeks of age (91% compliance rate), 730 had elevated rates of excretion of cystine and the dibasic amino acids lysine, ornithine, and arginine; 191 infants had persistent "infantile cystinuria" on follow-up screening (100% compliance). Apparent incidence of the phenotype was 562 per million infants; this rate is seven times higher than for classic cystinuria in the adult segment of the Quebec population. We studied longitudinally 26 probands 2 to 4 months of age. Initially, each excreted cystine and dibasic amino acids at much higher levels than did normal infants or either parent. From parental phenotypes (heterozygous or homozygous normal) and urine amino acid excretion values at 6 months of age in probands, the infants were classified as either heterozygous for the various classic cystinuria genotypes--type I ("silent"), eight infants; type II (high excretor), three; type III (moderate excretor), nine--or homozygous (and genetic compound), six. Urine amino acid excretion diminished steadily with age, to reach the variant parental value in heterozygous infants but not in homozygotes. Cystinuria heterozygotes, with the possible exception of some type I individuals, could not be distinguished reliably from homozygotes in early infancy, although homozygotes had significantly higher excretion values as a group. We deduce that renal ontogeny amplifies phenotypic expression of cystinuria alleles, thus influencing correct classification of genotype (heterozygote vs homozygote, and type of allele). These findings have implications for counseling and the need for follow-up of infantile cystinuria.
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Affiliation(s)
- Arabella Smith
- Oliver Latham LaboratoryDepartment of HealthPO Box 53North RydeNSW2113
| | - Bridget Wilcken
- Oliver Latham LaboratoryDepartment of HealthPO Box 53North RydeNSW2113
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