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李 映, 王 冬, 周 茂, 孙 浩, 洪 思, 蒋 莉, 郭 艺. [Leigh syndrome caused by the mitochondrial m.8993T>G mutation with hypocitrullinemia: a report of four cases and literature review]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2024; 26:940-945. [PMID: 39267509 PMCID: PMC11404460 DOI: 10.7499/j.issn.1008-8830.2404036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 08/05/2024] [Indexed: 09/17/2024]
Abstract
OBJECTIVES To explore early diagnostic biological markers for Leigh syndrome caused by the m.8993T>G mutation. METHODS A retrospective analysis was performed on the clinical data of four children diagnosed with m.8993T>G mutation-related mitochondrial disease at the Children's Hospital of Chongqing Medical University from January 2014 to January 2024. Additionally, a literature review was conducted. RESULTS All four children had plasma amino acid and acylcarnitine analyses that revealed decreased citrulline levels, and one child was initially identified through neonatal genetic metabolic disease screening. According to the literature review, there were 26 children with mitochondrial disease and hypocitrullinemia caused by the m.8993T>G mutation (including the four children in this study). Among these, 12 children exhibited clinical phenotypes of Leigh syndrome or Leigh-like syndrome, while 18 children were identified with hypocitrullinemia and/or elevated levels of 3-hydroxyisovalerylcarnitine (C5-OH) during neonatal genetic metabolic disease screening. CONCLUSIONS Hypocitrullinemia may serve as a potential biomarker for the early diagnosis of m.8993T>G mutation-associated Leigh syndrome, detectable as early as during neonatal genetic metabolic disease screening.
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Tauchmannová K, Pecinová A, Houštěk J, Mráček T. Variability of Clinical Phenotypes Caused by Isolated Defects of Mitochondrial ATP Synthase. Physiol Res 2024; 73:S243-S278. [PMID: 39016153 PMCID: PMC11412354 DOI: 10.33549/physiolres.935407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 06/28/2024] [Indexed: 08/09/2024] Open
Abstract
Disorders of ATP synthase, the key enzyme in mitochondrial energy supply, belong to the most severe metabolic diseases, manifesting as early-onset mitochondrial encephalo-cardiomyopathies. Since ATP synthase subunits are encoded by both mitochondrial and nuclear DNA, pathogenic variants can be found in either genome. In addition, the biogenesis of ATP synthase requires several assembly factors, some of which are also hotspots for pathogenic variants. While variants of MT-ATP6 and TMEM70 represent the most common cases of mitochondrial and nuclear DNA mutations respectively, the advent of next-generation sequencing has revealed new pathogenic variants in a number of structural genes and TMEM70, sometimes with truly peculiar genetics. Here we present a systematic review of the reported cases and discuss biochemical mechanisms, through which they are affecting ATP synthase. We explore how the knowledge of pathophysiology can improve our understanding of enzyme biogenesis and function. Keywords: Mitochondrial diseases o ATP synthase o Nuclear DNA o Mitochondrial DNA o TMEM70.
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Affiliation(s)
- K Tauchmannová
- Laboratory of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
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Verma A, Lehman AN, Gokcan H, Cropcho L, Black D, Dobrowolski SF, Vockley J, Bedoyan JK. Amino acid ratio combinations as biomarkers for discriminating patients with pyruvate dehydrogenase complex deficiency from other inborn errors of metabolism. Mol Genet Genomic Med 2024; 12:e2283. [PMID: 37688338 PMCID: PMC10767461 DOI: 10.1002/mgg3.2283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/17/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
BACKGROUND Pyruvate dehydrogenase complex deficiency (PDCD) is a mitochondrial neurometabolic disorder of energy deficit, with incidence of about 1 in 42,000 live births annually in the USA. The median and mean ages of diagnosis of PDCD are about 12 and 31 months, respectively. PDCD is a major cause of primary lactic acidosis with concomitant elevation in blood alanine (Ala) and proline (Pro) concentrations depending on phenotypic severity. Alanine/Leucine (Ala/Leu) ≥4.0 and Proline/Leucine (Pro/Leu) ≥3.0 combination cutoff from dried blood spot specimens was used as a biomarker for early identification of neonates/infants with PDCD. Further investigations were needed to evaluate the sensitivity (SN), specificity (SP), and clinical utility of such amino acid (AA) ratio combination cutoffs in discriminating PDCD from other inborn errors of metabolism (IEM) for early identification of such patients. METHODS We reviewed medical records of patients seen at UPMC in the past 11 years with molecularly or enzymatically confirmed diagnosis. We collected plasma AA analysis data from samples prior to initiation of therapeutic interventions such as total parenteral nutrition and/or ketogenic diet. Conditions evaluated included organic acidemias, primary mitochondrial disorders (MtDs), fatty acid oxidation disorders (FAOD), other IEMs on current newborn screening panels, congenital cardiac great vessel anomalies, renal tubular acidosis, and non-IEMs. The utility of specific AA ratio combinations as biomarkers were evaluated using receiver operating characteristic curves, correlation analysis, principal component analysis, and cutoff SN, SP, and positive predictive value determined from 201 subjects with broad age range. RESULTS Alanine/Lysine (Ala/Lys) and Ala/Leu as well as (Ala + Pro)/(Leu + Lys) and Ala/Leu ratio combinations effectively discriminated subjects with PDCD from those with other MtDs and IEMs on current newborn screening panels. Specific AA ratio combinations were significantly more sensitive in identifying PDCD than Ala alone or combinations of Ala and/or Pro in the evaluated cohort of subjects. Ala/Lys ≥3.0 and Ala/Leu ≥5.0 as well as (Ala + Pro)/(Leu + Lys) ≥2.5 and Ala/Leu ≥5.0 combination cutoffs identified patients with PDCD with 100% SN and ~85% SP. CONCLUSIONS With the best predictor of survival and positive cognitive outcome in PDCD being age of diagnosis, PDCD patients would benefit from use of such highly SN and SP AA ratio combination cutoffs as biomarkers for early identification of at-risk newborns, infants, and children, for early intervention(s) with known and/or novel therapeutics for this disorder.
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Affiliation(s)
- Anisha Verma
- West Virginia School of Osteopathic MedicineLewisburgWest VirginiaUSA
| | - April N. Lehman
- UPMC Children's Hospital of PittsburghPittsburghPennsylvaniaUSA
| | - Hatice Gokcan
- Department of ChemistryCarnegie Mellon UniversityPittsburghPennsylvaniaUSA
| | - Lorna Cropcho
- UPMC Children's Hospital of PittsburghPittsburghPennsylvaniaUSA
| | - Danielle Black
- UPMC Children's Hospital of PittsburghPittsburghPennsylvaniaUSA
| | - Steven F. Dobrowolski
- UPMC Children's Hospital of PittsburghPittsburghPennsylvaniaUSA
- Department of PathologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Jerry Vockley
- UPMC Children's Hospital of PittsburghPittsburghPennsylvaniaUSA
- Division of Genetic and Genomic Medicine, Department of PediatricsUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Jirair K. Bedoyan
- UPMC Children's Hospital of PittsburghPittsburghPennsylvaniaUSA
- Division of Genetic and Genomic Medicine, Department of PediatricsUniversity of PittsburghPittsburghPennsylvaniaUSA
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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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Hall PL, Wittenauer AL, Wilcox WR. Proximal urea cycle defects are challenging to detect with newborn screening: Results of a prospective pilot study using post-analytical tools. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:178-186. [PMID: 36097743 DOI: 10.1002/ajmg.c.31996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 07/26/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
The purpose of this pilot project was to evaluate the efficacy of the Collaborative Integrated Laboratory Reports (CLIR) postanalytical tools from Mayo Clinic for detection of newborns with proximal urea cycle disorders (PUCD) in the Georgia newborn screening program that uses the underivatized Neobase2 kit (Perkin Elmer). We evaluated 138,560 newborn screening (NBS) samples (between 125,000 and 130,000 children) and used the CLIR result interpretation guidelines to stratify results. Children at higher risk of having a PUCD received follow-up services including confirmatory lab testing (ammonia, plasma amino acids, urine orotic acid) or a repeat NBS sample. We made multiple adjustments to our CLIR PUCD tool and to our follow-up algorithms in order to reduce false positives. Regardless, a high number of NBS samples resulted with false positives in part due to the glutamine peak also containing lysine. No children were diagnosed with a PUCD during our study period, and the Emory Genetics Metabolic Center is unaware of any children diagnosed outside of the NBS system during that time. Based on our experience, PUCD is not suitable for statewide NBS using Neobase2 and CLIR. Other methodologies that can separate glutamine from other amino acids may have better performance.
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Affiliation(s)
| | - Angela Lynn Wittenauer
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - William Ross Wilcox
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
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Zeviani M, Carelli V. Mitochondrial Retinopathies. Int J Mol Sci 2021; 23:210. [PMID: 35008635 PMCID: PMC8745158 DOI: 10.3390/ijms23010210] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/14/2021] [Accepted: 12/18/2021] [Indexed: 12/13/2022] Open
Abstract
The retina is an exquisite target for defects of oxidative phosphorylation (OXPHOS) associated with mitochondrial impairment. Retinal involvement occurs in two ways, retinal dystrophy (retinitis pigmentosa) and subacute or chronic optic atrophy, which are the most common clinical entities. Both can present as isolated or virtually exclusive conditions, or as part of more complex, frequently multisystem syndromes. In most cases, mutations of mtDNA have been found in association with mitochondrial retinopathy. The main genetic abnormalities of mtDNA include mutations associated with neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP) sometimes with earlier onset and increased severity (maternally inherited Leigh syndrome, MILS), single large-scale deletions determining Kearns-Sayre syndrome (KSS, of which retinal dystrophy is a cardinal symptom), and mutations, particularly in mtDNA-encoded ND genes, associated with Leber hereditary optic neuropathy (LHON). However, mutations in nuclear genes can also cause mitochondrial retinopathy, including autosomal recessive phenocopies of LHON, and slowly progressive optic atrophy caused by dominant or, more rarely, recessive, mutations in the fusion/mitochondrial shaping protein OPA1, encoded by a nuclear gene on chromosome 3q29.
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Affiliation(s)
- Massimo Zeviani
- Department of Neurosciences, The Clinical School, University of Padova, 35128 Padova, Italy
- Veneto Institute of Molecular Medicine, Via Orus 2, 35128 Padova, Italy
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40139 Bologna, Italy
- Programma di Neurogenetica, IRCCS Istituto delle Scienze Neurologiche di Bologna, Via Altura 6, 40139 Bologna, Italy
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Peretz RH, Ah Mew N, Vernon HJ, Ganetzky RD. Prospective diagnosis of MT-ATP6-related mitochondrial disease by newborn screening. Mol Genet Metab 2021; 134:37-42. [PMID: 34176718 PMCID: PMC8578202 DOI: 10.1016/j.ymgme.2021.06.007] [Citation(s) in RCA: 10] [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: 05/06/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 11/24/2022]
Abstract
Elevated citrulline and C5-OH levels are reported as part of the newborn screening of core and secondary disorders on the Recommended Uniform Screening Panel (RUSP). Additionally, some state laboratory newborn screening programs report low citrulline levels, which may be observed in proximal urea cycle disorders. We report six patients who were found on newborn screening to have low citrulline and/or elevated C5-OH levels in whom confirmatory testing showed the combination of these two abnormal analytes. Mitochondrial sequencing revealed known pathogenic variants in MT-ATP6 at high heteroplasmy levels in all cases. MT-ATP6 at these heteroplasmy levels is associated with Leigh syndrome, a progressive neurodegenerative disease. Patients were treated with supplemental citrulline and, in some cases, mitochondrial cofactor therapy. These six patients have not experienced metabolic crises or developmental regression, and early diagnosis and management may help prevent the neurological sequelae of Leigh syndrome. The affected mothers and siblings are asymptomatic or paucisymptomatic (e.g. intellectual disability, depression, migraines, obsessive-compulsive disorder, and poor balance) despite high heteroplasmy or apparent homoplasmy of the familial variant, thus expanding the clinical spectrum seen in pathogenic variants of MT-ATP6. Confirmatory plasma amino acid analysis and acylcarnitine profiling should be ordered in a patient with either low citrulline and/or elevated C5-OH, as this combination appears specific for pathogenic variants in MT-ATP6.
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Affiliation(s)
- Ryan H Peretz
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Nicholas Ah Mew
- Rare Disease Institute, Children's National Hospital, Washington, DC, United States
| | - Hilary J Vernon
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Rebecca D Ganetzky
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, United States; Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States.
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Tinkov AA, Skalnaya MG, Skalny AV. Serum trace element and amino acid profile in children with cerebral palsy. J Trace Elem Med Biol 2021; 64:126685. [PMID: 33249374 DOI: 10.1016/j.jtemb.2020.126685] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/16/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND The existing data demonstrate that both trace elements and amino acids play a significant role in neurodevelopment and brain functioning. Certain studies have demonstrated alteration of micronutrient status in children with cerebral palsy, although multiple inconsistencies exist. THE OBJECTIVE of the present study was to assess serum trace element and mineral, as well as amino acid levels in children with cerebral palsy. METHODS 71 children with cerebral palsy (39 boys and 32 girls, 5.7 ± 2.3 y.o.) and 84 healthy children (51 boys and 33 girls, 5.4 ± 2.3 y.o.) were enrolled in the present study. Serum trace element and mineral levels were assessed using inductively-coupled plasma mass-spectrometry (ICP-MS). Amino acid profile was evaluated by means of high-pressure liquid chromatography (HPLC). RESULTS Children with cerebral palsy are characterized by significantly lower Cu and Zn levels by 6% and 8%, whereas serum I concentration exceeded the control values by 7%. A tendency to increased serum Mn and Se levels was also observed in patients with cerebral palsy. Serum citrulline, leucine, tyrosine, and valine levels were 15 %, 23 %, 15 %, and 11 % lower than those in healthy controls. Nearly twofold lower levels of serum proline were accompanied by a 44 % elevation of hydroxyproline concentrations when compared to the control values. In multiple regression model serum I, Zn, and hydroxyproline levels were found to be independently associated with the presence of cerebral palsy. Correlation analysis demonstrated a significant correlation between Cu, Mn, Se, I, and Zn levels with hydroxyproline and citrulline concentrations. CONCLUSION The observed alterations in trace element and amino acid metabolism may contribute to neurological deterioration in cerebral palsy. However, the cross-sectional design of the study does not allow to estimate the causal trilateral relationships between cerebral palsy, altered trace element, and amino acid metabolism.
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Bedoyan JK, Hage R, Shin HK, Linard S, Ferren E, Ducich N, Wilson K, Lehman A, Schillaci L, Manickam K, Mori M, Bartholomew D, DeBrosse S, Cohen B, Parikh S, Kerr D. Utility of specific amino acid ratios in screening for pyruvate dehydrogenase complex deficiencies and other mitochondrial disorders associated with congenital lactic acidosis and newborn screening prospects. JIMD Rep 2020; 56:70-81. [PMID: 33204598 PMCID: PMC7653239 DOI: 10.1002/jmd2.12153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/09/2020] [Accepted: 07/16/2020] [Indexed: 01/24/2023] Open
Abstract
Pyruvate dehydrogenase complex deficiencies (PDCDs) and other mitochondrial disorders (MtDs) can (a) result in congenital lactic acidosis with elevations of blood alanine (Ala) and proline (Pro), (b) lead to decreased ATP production, and (c) result in high morbidity and mortality. With ~140,000 live births annually in Ohio and ~1 in 9,000 overall prevalence of MtDs, we estimate 2 to 3 newborns will have PDCD and 13 to 14 others likely will have another MtD annually. We compared the sensitivities of plasma amino acids (AA) Alanine (Ala), Alanine:Leucine (Ala:Leu), Alanine:Lysine and the combination of Ala:Leu and Proline:Leucine (Pro:Leu), in subjects with known primary-specific PDCD due to PDHA1 and PDHB mutations vs controls. Furthermore, in collaboration with the Ohio newborn screening (NBS) laboratory, we determined Ala and Pro concentrations in dried blood spot (DBS) specimens using existing NBS analytic approaches and evaluated Ala:Leu and Pro:Leu ratios from DBS specimens of 123,414 Ohio newborns in a 12-month period. We used the combined Ala:Leu ≥4.0 and Pro:Leu ≥3.0 ratio criterion from both DBS and plasma specimens as a screening tool in our retrospective review of newborn data. The screening tool applied on DBS and/or plasma (or serum) AA specimens successfully identified three unrelated females with novel de novo PDHA1 mutations, one male with a novel de novo X-linked HSD17B10 mutation, and a female with VARS2 mutations. This work lays the first step for piloting an NBS protocol in Ohio for identifying newborns at high risk for primary-specific PDCD and other MtDs who might benefit from neonatal diagnosis and early institution of known therapy and/or potential novel therapies for such disorders.
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Affiliation(s)
- Jirair K. Bedoyan
- Departments of Genetics and Genome SciencesCase Western Reserve University (CWRU)ClevelandOhioUSA
- PediatricsCWRUClevelandOhioUSA
- Center for Human GeneticsUniversity Hospitals Cleveland Medical Center (UHCMC)ClevelandOhioUSA
- Center for Inherited Disorders of Energy Metabolism (CIDEM)UHCMCClevelandOhioUSA
| | - Rosemary Hage
- Newborn Screening and Radiation ChemistryOhio Department of Health LaboratoryColumbusOhioUSA
| | | | - Sharon Linard
- Newborn Screening and Radiation ChemistryOhio Department of Health LaboratoryColumbusOhioUSA
| | - Edwin Ferren
- PediatricsCWRUClevelandOhioUSA
- Center for Human GeneticsUniversity Hospitals Cleveland Medical Center (UHCMC)ClevelandOhioUSA
| | | | | | - April Lehman
- Nationwide Children's Hospital (NCH) and The Ohio State University College of MedicineSection of Genetic and Genomic MedicineColumbusOhioUSA
| | - Lori‐Anne Schillaci
- Departments of Genetics and Genome SciencesCase Western Reserve University (CWRU)ClevelandOhioUSA
- PediatricsCWRUClevelandOhioUSA
- Center for Human GeneticsUniversity Hospitals Cleveland Medical Center (UHCMC)ClevelandOhioUSA
| | - Kandamurugu Manickam
- Nationwide Children's Hospital (NCH) and The Ohio State University College of MedicineSection of Genetic and Genomic MedicineColumbusOhioUSA
| | - Mari Mori
- Nationwide Children's Hospital (NCH) and The Ohio State University College of MedicineSection of Genetic and Genomic MedicineColumbusOhioUSA
| | - Dennis Bartholomew
- Nationwide Children's Hospital (NCH) and The Ohio State University College of MedicineSection of Genetic and Genomic MedicineColumbusOhioUSA
| | - Suzanne DeBrosse
- Departments of Genetics and Genome SciencesCase Western Reserve University (CWRU)ClevelandOhioUSA
- PediatricsCWRUClevelandOhioUSA
- Center for Human GeneticsUniversity Hospitals Cleveland Medical Center (UHCMC)ClevelandOhioUSA
| | - Bruce Cohen
- Department of PediatricsAkron Children's Hospital (ACH) Rebecca D. Considine Research InstituteAkronOhioUSA
- Northeast Ohio Medical UniversityRootstownOhioUSA
| | - Sumit Parikh
- The Cleveland Clinic Foundation (CCF), Neurosciences InstituteClevelandOhioUSA
| | - Douglas Kerr
- PediatricsCWRUClevelandOhioUSA
- Center for Inherited Disorders of Energy Metabolism (CIDEM)UHCMCClevelandOhioUSA
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Clinical syndromes associated with mtDNA mutations: where we stand after 30 years. Essays Biochem 2018; 62:235-254. [DOI: 10.1042/ebc20170097] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/16/2023]
Abstract
The landmark year 1988 can be considered as the birthdate of mitochondrial medicine, when the first pathogenic mutations affecting mtDNA were associated with human diseases. Three decades later, the field still expands and we are not ‘scraping the bottom of the barrel’ yet. Despite the tremendous progress in terms of molecular characterization and genotype/phenotype correlations, for the vast majority of cases we still lack a deep understanding of the pathogenesis, good models to study, and effective therapeutic options. However, recent technological advances including somatic cell reprogramming to induced pluripotent stem cells (iPSCs), organoid technology, and tailored endonucleases provide unprecedented opportunities to fill these gaps, casting hope to soon cure the major primary mitochondrial phenotypes reviewed here. This group of rare diseases represents a key model for tackling the pathogenic mechanisms involving mitochondrial biology relevant to much more common disorders that affect our currently ageing population, such as diabetes and metabolic syndrome, neurodegenerative and inflammatory disorders, and cancer.
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Ganetzky RD, Falk MJ. 8-year retrospective analysis of intravenous arginine therapy for acute metabolic strokes in pediatric mitochondrial disease. Mol Genet Metab 2018; 123:301-308. [PMID: 29428506 PMCID: PMC5849405 DOI: 10.1016/j.ymgme.2018.01.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 01/31/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Intravenous (IV) arginine has been reported to ameliorate acute metabolic stroke symptoms in adult patients with Mitochondrial Encephalopathy with Lactic Acidosis and Stroke-like Episodes (MELAS) syndrome, where its therapeutic benefit is postulated to result from arginine acting as a nitric oxide donor to reverse vasospasm. Further, reduced plasma arginine may occur in mitochondrial disease since the biosynthesis of arginine's precursor, citrulline, requires ATP. Metabolic strokes occur across a wide array of primary mitochondrial diseases having diverse molecular etiologies that are likely to share similar pathophysiologic mechanisms. Therefore, IV arginine has been increasingly used for the acute clinical treatment of metabolic stroke across a broad mitochondrial disease population. METHODS We performed retrospective analysis of a large cohort of subjects who were under 18 years of age at IRB #08-6177 study enrollment and had molecularly-confirmed primary mitochondrial disease (n = 71, excluding the common MELAS m.3243A>G mutation). 9 unrelated subjects in this cohort received acute arginine IV treatment for one or more stroke-like episodes (n = 17 total episodes) between 2009 and 2016 at the Children's Hospital of Philadelphia. Retrospectively reviewed data included subject genotype, clinical symptoms, age, arginine dosing, neuroimaging (if performed), prophylactic therapies, and adverse events. RESULTS Genetic etiologies of subjects who presented with acute metabolic strokes included 4 mitochondrial DNA (mtDNA) pathogenic point mutations, 1 mtDNA deletion, and 4 nuclear gene disorders. Subject age ranged from 19 months to 23 years at the time of any metabolic stroke episode (median, 8 years). 3 subjects had recurrent stroke episodes. 70% of subjects were on prophylactic arginine or citrulline therapy at the time of a stroke-like episode. IV arginine was initiated on initial presentation in 65% of cases. IV arginine was given for 1-7 days (median, 1 day). A positive clinical response to IV arginine occurred in 47% of stroke-like episodes; an additional 6% of episodes showed clinical benefit from multiple simultaneous treatments that included arginine, confounding sole interpretation of arginine effect. All IV arginine-responsive stroke-like episodes (n = 8) received treatment immediately on presentation (p = .003). Interestingly, the presence of unilateral symptoms strongly predicted arginine response (p = .02, Chi-Square); however, almost all of these cases immediately received IV arginine, confounding interpretation of causality direction. Suggestive trends toward increased IV arginine response were seen in subjects with mtDNA relative to nDNA mutations and in older pediatric subjects, although statistical significance was not reached possibly due to small sample size. No adverse events, including hypotensive episodes, from IV arginine therapy were reported. CONCLUSIONS Single-center retrospective analysis suggests that IV arginine therapy yields significant therapeutic benefit with little risk in pediatric mitochondrial disease stroke subjects across a wide range of genetic etiologies beyond classical MELAS. Acute hemiplegic stroke, in particular, was highly responsive to IV arginine treatment. Prospective studies with consistent arginine dosing, and pre- and post-neuroimaging, will further inform the clinical utility of IV arginine therapy for acute metabolic stroke in pediatric mitochondrial disease.
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Affiliation(s)
- Rebecca D Ganetzky
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marni J Falk
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Balasubramaniam S, Lewis B, Mock DM, Said HM, Tarailo-Graovac M, Mattman A, van Karnebeek CD, Thorburn DR, Rodenburg RJ, Christodoulou J. Leigh-Like Syndrome Due to Homoplasmic m.8993T>G Variant with Hypocitrullinemia and Unusual Biochemical Features Suggestive of Multiple Carboxylase Deficiency (MCD). JIMD Rep 2016; 33:99-107. [PMID: 27450367 DOI: 10.1007/8904_2016_559] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 03/09/2016] [Accepted: 03/16/2016] [Indexed: 01/15/2023] Open
Abstract
Leigh syndrome (LS), or subacute necrotizing encephalomyelopathy, is a genetically heterogeneous, relentlessly progressive, devastating neurodegenerative disorder that usually presents in infancy or early childhood. A diagnosis of Leigh-like syndrome may be considered in individuals who do not fulfil the stringent diagnostic criteria but have features resembling Leigh syndrome.We describe a unique presentation of Leigh-like syndrome in a 3-year-old boy with elevated 3-hydroxyisovalerylcarnitine (C5-OH) on newborn screening (NBS). Subsequent persistent plasma elevations of C5-OH and propionylcarnitine (C3) as well as fluctuating urinary markers were suggestive of multiple carboxylase deficiency (MCD). Normal enzymology and mutational analysis of genes encoding holocarboxylase synthetase (HLCS) and biotinidase (BTD) excluded MCD. Biotin uptake studies were normal excluding biotin transporter deficiency. His clinical features at 13 months of age comprised psychomotor delay, central hypotonia, myopathy, failure to thrive, hypocitrullinemia, recurrent episodes of decompensation with metabolic keto-lactic acidosis and an episode of hyperammonemia. Biotin treatment from 13 months of age was associated with increased patient activity, alertness, and attainment of new developmental milestones, despite lack of biochemical improvements. Whole exome sequencing (WES) analysis failed to identify any other variants which could likely contribute to the observed phenotype, apart from the homoplasmic (100%) m.8993T>G variant initially detected by mitochondrial DNA (mtDNA) sequencing.Hypocitrullinemia has been reported in patients with the m.8993T>G variant and other mitochondrial disorders. However, persistent plasma elevations of C3 and C5-OH have previously only been reported in one other patient with this homoplasmic mutation. We suggest considering the m.8993T>G variant early in the diagnostic evaluation of MCD-like biochemical disturbances, particularly when associated with hypocitrullinemia on NBS and subsequent confirmatory tests. An oral biotin trial is also warranted.
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Affiliation(s)
- Shanti Balasubramaniam
- Metabolic Unit, Department of Rheumatology and Metabolic Medicine, Princess Margaret Hospital, Perth, WA, Australia. .,School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia. .,Western Sydney Genetics Program, Children's Hospital at Westmead, Westmead, NSW, Australia.
| | - B Lewis
- PathWest Laboratories WA, Princess Margaret Hospital, Perth, WA, Australia
| | - D M Mock
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - H M Said
- Department of Medicine, University of California School of Medicine Irvine, Irvine, CA, USA
| | - M Tarailo-Graovac
- Centre for Molecular Medicine, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - A Mattman
- Adult Metabolic Diseases Clinic, Division of Endocrinology and Metabolism, Vancouver General Hospital, UBC, Vancouver, BC, Canada
| | - C D van Karnebeek
- Centre for Molecular Medicine, Department of Pediatrics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - D R Thorburn
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - R J Rodenburg
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J Christodoulou
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
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Finsterer J, Zarrouk-Mahjoub S, Daruich A. The Eye on Mitochondrial Disorders. J Child Neurol 2016; 31:652-62. [PMID: 26275973 DOI: 10.1177/0883073815599263] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 07/08/2015] [Indexed: 11/16/2022]
Abstract
Ophthalmologic manifestations of mitochondrial disorders are frequently neglected or overlooked because they are often not regarded as part of the phenotype. This review aims at summarizing and discussing the etiology, pathogenesis, diagnosis, and treatment of ophthalmologic manifestations of mitochondrial disorders. Review of publications about ophthalmologic involvement in mitochondrial disorders by search of Medline applying appropriate search terms. The eye is frequently affected by syndromic as well as nonsyndromic mitochondrial disorders. Primary and secondary ophthalmologic manifestations can be differentiated. The most frequent ophthalmologic manifestations of mitochondrial disorders include ptosis, progressive external ophthalmoplegia, optic atrophy, retinopathy, and cataract. More rarely occurring are nystagmus and abnormalities of the cornea, ciliary body, intraocular pressure, the choroidea, or the brain secondarily affecting the eyes. It is important to recognize and diagnose ophthalmologic manifestations of mitochondrial disorders as early as possible because most are accessible to symptomatic treatment with partial or complete short-term or long-term beneficial effect. Ophthalmologic manifestations of mitochondrial disorders need to be appropriately diagnosed to initiate the most effective management and guarantee optimal outcome.
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Affiliation(s)
| | | | - Alejandra Daruich
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Switzerland
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