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Savvidou A, Sofou K, Eklund EA, Aronsson J, Darin N. Manifestations of X-linked pyruvate dehydrogenase complex deficiency in female PDHA1 carriers. Eur J Neurol 2024:e16283. [PMID: 38497591 DOI: 10.1111/ene.16283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/26/2024] [Accepted: 03/05/2024] [Indexed: 03/19/2024]
Abstract
BACKGROUND AND PURPOSE Pyruvate dehydrogenase complex deficiency is in up to 90% caused by pathogenic variants in the X-linked PDHA1 gene. We aimed to investigate female relatives of index patients with PDHA1-related disease to (i) describe the prevalence of female PDHA1 carriers, (ii) determine whether they had symptoms and signs, and (iii) delineate the associated phenotype. METHODS In a national population-based study, we identified 37 patients with pathogenic variants in PDHA1. Sanger sequencing for the presence of the pathogenic variant was performed in their mothers and female relatives. The identified female carriers were clinically assessed, and their medical records were reviewed. RESULTS The proportion carrying a de novo variant was 86%. We identified seven female PDHA1 carriers from five families. Five of them exhibited clinical features of the disease and were previously undiagnosed; all had signs of peripheral axonal neuropathy, four presented with strokelike episodes including two with Leigh-like lesions, and three had facial stigmata. CONCLUSIONS PDHA1-related disease is underrecognized in heterozygous female carriers. Peripheral axonal neuropathy, strokelike and Leigh-like changes, and facial dysmorphism should raise suspicion of the disorder. Genetic analysis and clinical examination of potential female carriers are important for genetic counseling and have implications for treatment.
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Affiliation(s)
- Antri Savvidou
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Pediatrics, Queen Silvia Children's Hospital, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Kalliopi Sofou
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Pediatrics, Queen Silvia Children's Hospital, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Erik A Eklund
- Section of Pediatrics, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Johan Aronsson
- Department of Pediatrics, Ryhov Hospital, Jönköping, Sweden
| | - Niklas Darin
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Pediatrics, Queen Silvia Children's Hospital, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
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Álvarez-Córdoba M, Talaverón-Rey M, Povea-Cabello S, Cilleros-Holgado P, Gómez-Fernández D, Piñero-Pérez R, Reche-López D, Munuera-Cabeza M, Suárez-Carrillo A, Romero-González A, Romero-Domínguez JM, López-Cabrera A, Armengol JÁ, Sánchez-Alcázar JA. Patient-Derived Cellular Models for Polytarget Precision Medicine in Pantothenate Kinase-Associated Neurodegeneration. Pharmaceuticals (Basel) 2023; 16:1359. [PMID: 37895830 PMCID: PMC10609847 DOI: 10.3390/ph16101359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/21/2023] [Accepted: 09/21/2023] [Indexed: 10/29/2023] Open
Abstract
The term neurodegeneration with brain iron accumulation (NBIA) brings together a broad set of progressive and disabling neurological genetic disorders in which iron is deposited preferentially in certain areas of the brain. Among NBIA disorders, the most frequent subtype is pantothenate kinase-associated neurodegeneration (PKAN) caused by pathologic variants in the PANK2 gene codifying the enzyme pantothenate kinase 2 (PANK2). To date, there are no effective treatments to stop the progression of these diseases. This review discusses the utility of patient-derived cell models as a valuable tool for the identification of pharmacological or natural compounds for implementing polytarget precision medicine in PKAN. Recently, several studies have described that PKAN patient-derived fibroblasts present the main pathological features associated with the disease including intracellular iron overload. Interestingly, treatment of mutant cell cultures with various supplements such as pantothenate, pantethine, vitamin E, omega 3, α-lipoic acid L-carnitine or thiamine, improved all pathophysiological alterations in PKAN fibroblasts with residual expression of the PANK2 enzyme. The information provided by pharmacological screenings in patient-derived cellular models can help optimize therapeutic strategies in individual PKAN patients.
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Affiliation(s)
- Mónica Álvarez-Córdoba
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Marta Talaverón-Rey
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Suleva Povea-Cabello
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Paula Cilleros-Holgado
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - David Gómez-Fernández
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Rocío Piñero-Pérez
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Diana Reche-López
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Manuel Munuera-Cabeza
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Alejandra Suárez-Carrillo
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Ana Romero-González
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Jose Manuel Romero-Domínguez
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - Alejandra López-Cabrera
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
| | - José Ángel Armengol
- Department of Physiology, Anatomy and Cellular Biology, Pablo de Olavide University, 41013 Seville, Spain;
| | - José Antonio Sánchez-Alcázar
- Andalusian Centre for Developmental Biology (CABD-CSIC-Pablo de Olavide University), 41013 Seville, Spain; (M.Á.-C.); (M.T.-R.); (S.P.-C.); (P.C.-H.); (D.G.-F.); (R.P.-P.); (D.R.-L.); (M.M.-C.); (A.S.-C.); (A.R.-G.); (J.M.R.-D.); (A.L.-C.)
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Leuzzi V, Galosi S. Experimental pharmacology: Targeting metabolic pathways. Int Rev Neurobiol 2023; 169:259-315. [PMID: 37482395 DOI: 10.1016/bs.irn.2023.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Since the discovery of the treatment for Wilson disease a growing number of treatable inherited dystonias have been identified and their search and treatment have progressively been implemented in the clinics of patients with dystonia. While waiting for gene therapy to be more widely and adequately translated into the clinical setting, the efforts to divert the natural course of dystonia reside in unveiling its pathogenesis. Specific metabolic treatments can rewrite the natural history of the disease by preventing neurotoxic metabolite accumulation or interfering with the cell accumulation of damaging metabolites, restoring energetic cell fuel, supplementing defective metabolites, and supplementing the defective enzyme. A metabolic derangement of cell homeostasis is part of the progression of many non-metabolic genetic lesions and could be the target for possible metabolic approaches. In this chapter, we provided an update on treatment strategies for treatable inherited dystonias and an overview of genetic dystonias with new experimental therapeutic approaches available or close to clinical translation.
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Affiliation(s)
- Vincenzo Leuzzi
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Serena Galosi
- Department of Human Neuroscience, Sapienza University, Rome, Italy.
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Ogawa E, Hishiki T, Hayakawa N, Suzuki H, Kosaki K, Suematsu M, Takenouchi T. Ketogenic diet in action: Metabolic profiling of pyruvate dehydrogenase deficiency. Mol Genet Metab Rep 2023; 35:100968. [PMID: 36974075 PMCID: PMC10038782 DOI: 10.1016/j.ymgmr.2023.100968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/12/2023] [Accepted: 03/12/2023] [Indexed: 03/29/2023] Open
Abstract
The pyruvate dehydrogenase complex serves as the main connection between cytosolic glycolysis and the tricarboxylic acid cycle within mitochondria. An infant with pyruvate dehydrogenase complex deficiency was treated with vitamin B1 supplementation and a ketogenic diet. These dietary modifications resolved the renal tubular reabsorption, central apnea, and transfusion-dependent anemia. A concurrent metabolome analysis demonstrated the resolution of the amino aciduria and an increased total amount of substrates in the tricarboxylic acid cycle, reflecting the improved mitochondrial energetics. Glutamate was first detected in the cerebrospinal fluid, accompanied by a clinical improvement, after the ketogenic ratio was increased to 3:1; thus, glutamate levels in cerebrospinal fluid may represent a biomarker for neuronal recovery. Metabolomic analyses of body fluids are useful for monitoring therapeutic effects in infants with inborn errors of carbohydrate metabolism.
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Affiliation(s)
- Eri Ogawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Takako Hishiki
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
| | - Noriyo Hayakawa
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
- Clinical and Translational Research Center, Keio University School of Medicine, Tokyo, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Makoto Suematsu
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
- Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
- Corresponding author.
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Croci C, Cataldi M, Baratto S, Bruno C, Trucco F, Doccini S, Romano A, Nesti C, Santorelli FM, Fiorillo C. Recurrent Sensory-Motor Neuropathy Mimicking CIDP as Predominant Presentation of PDH Deficiency. Neuropediatrics 2023; 54:211-216. [PMID: 36693417 DOI: 10.1055/a-2018-4845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Pyruvate dehydrogenase complex (PDH) deficiency (Online Mendelian Inheritance in Man # 312170) is a relatively common mitochondrial disorder, caused by mutations in the X-linked PDHA1 gene and presenting with a variable phenotypic spectrum, ranging from severe infantile encephalopathy to milder chronic neurological disorders.Isolated peripheral neuropathy as predominant clinical presentation is uncommon. RESULTS We report on a patient, now 21 years old, presenting at the age of 2 years with recurrent symmetric weakness as first symptom of a PDH deficiency. Neurophysiological evaluation proving a sensory-motor polyneuropathy with conduction blocks and presence of elevated cerebrospinal fluid proteins, suggested a chronic inflammatory demyelinating polyneuropathy. The evidence of high serum lactate and the alterations in oxidative metabolism in muscle biopsy pointed toward the final diagnosis. After starting nutritional supplements, no further episodes occurred. A hemizygous mutation in PDHA1 (p.Arg88Cys) was identified. This mutation has been previously described in five patients with a similar phenotype. A three-dimensional reconstruction demonstrated that mutations affecting this arginine destabilize the interactions between the subunits of the E1 complex. CONCLUSION We summarize the clinical and genetic characteristics of one patient with PDH deficiency presenting isolated peripheral nervous system involvement. This study highlights that the diagnosis of PDH deficiency should be considered in children with unexplained peripheral neuropathy, even with features suggestive of acquired forms, especially in case of early onset and limited response to treatment. A simple analysis of lactic acid could help to target the diagnosis.In addition, we suggest that the residue Arg88 is the most frequently involved in this specific phenotype of PDH deficiency.
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Affiliation(s)
- Carolina Croci
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
| | - Matteo Cataldi
- Department of Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Serena Baratto
- Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Claudio Bruno
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy.,Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Federica Trucco
- Department of Neurorehabilitation, University of Milan, Milan, Italy
| | - Stefano Doccini
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, Pisa, Italy
| | - Alessandro Romano
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology, IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Claudia Nesti
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, Pisa, Italy
| | - Filippo Maria Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, Pisa, Italy
| | - Chiara Fiorillo
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy.,Department of Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genova, Italy
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Whittle EF, Chilian M, Karimiani EG, Progri H, Buhas D, Kose M, Ganetzky RD, Toosi MB, Torbati PN, Badv RS, Shelihan I, Yang H, Elloumi HZ, Lee S, Jamshidi Y, Pittman AM, Houlden H, Ignatius E, Rahman S, Maroofian R, Yoon WH, Carroll CJ. Biallelic variants in OGDH encoding oxoglutarate dehydrogenase lead to a neurodevelopmental disorder characterized by global developmental delay, movement disorder, and metabolic abnormalities. Genet Med 2023; 25:100332. [PMID: 36520152 DOI: 10.1016/j.gim.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/01/2022] [Accepted: 11/01/2022] [Indexed: 12/23/2022] Open
Abstract
PURPOSE This study aimed to establish the genetic cause of a novel autosomal recessive neurodevelopmental disorder characterized by global developmental delay, movement disorder, and metabolic abnormalities. METHODS We performed a detailed clinical characterization of 4 unrelated individuals from consanguineous families with a neurodevelopmental disorder. We used exome sequencing or targeted-exome sequencing, cosegregation, in silico protein modeling, and functional analyses of variants in HEK293 cells and Drosophila melanogaster, as well as in proband-derived fibroblast cells. RESULTS In the 4 individuals, we identified 3 novel homozygous variants in oxoglutarate dehydrogenase (OGDH) (NM_002541.3), which encodes a subunit of the tricarboxylic acid cycle enzyme α-ketoglutarate dehydrogenase. In silico homology modeling predicts that c.566C>T:p.(Pro189Leu) and c.890C>A:p.(Ser297Tyr) variants interfere with the structure and function of OGDH. Fibroblasts from individual 1 showed that the p.(Ser297Tyr) variant led to a higher degradation rate of the OGDH protein. OGDH protein with p.(Pro189Leu) or p.(Ser297Tyr) variants in HEK293 cells showed significantly lower levels than the wild-type protein. Furthermore, we showed that expression of Drosophila Ogdh (dOgdh) carrying variants homologous to p.(Pro189Leu) or p.(Ser297Tyr), failed to rescue developmental lethality caused by loss of dOgdh. SpliceAI, a variant splice predictor, predicted that the c.935G>A:p.(Arg312Lys)/p.(Phe264_Arg312del) variant impacts splicing, which was confirmed through a mini-gene assay in HEK293 cells. CONCLUSION We established that biallelic variants in OGDH cause a neurodevelopmental disorder with metabolic and movement abnormalities.
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Hayano S, Amamoto M, Naito E. Thiamine-responsive pyruvate dehydrogenase complex deficiency presenting as recurrent muscle weakness: Identification of a novel mutation (p.T111I) in the PDHA1 gene. Pediatr Int 2023; 65:e15385. [PMID: 36225105 PMCID: PMC10108131 DOI: 10.1111/ped.15385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 09/12/2022] [Accepted: 10/12/2022] [Indexed: 02/01/2023]
Affiliation(s)
- Shunsuke Hayano
- Department of PediatricsKitakyushu City Yahata HospitalFukuokaJapan
| | - Masano Amamoto
- Department of PediatricsKitakyushu City Yahata HospitalFukuokaJapan
| | - Etsuo Naito
- Department of PediatricsJapanese Red Cross Tokushima Hinomine Rehabilitation CenterKomatsujimaJapan
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Álvarez-Córdoba M, Reche-López D, Cilleros-Holgado P, Talaverón-Rey M, Villalón-García I, Povea-Cabello S, Suárez-Rivero JM, Suárez-Carrillo A, Munuera-Cabeza M, Piñero-Pérez R, Sánchez-Alcázar JA. Therapeutic approach with commercial supplements for pantothenate kinase-associated neurodegeneration with residual PANK2 expression levels. Orphanet J Rare Dis 2022; 17:311. [PMID: 35945593 PMCID: PMC9364590 DOI: 10.1186/s13023-022-02465-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/24/2022] [Indexed: 12/24/2022] Open
Abstract
Background Neurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic disorders frequently associated with iron accumulation in the basal nuclei of the brain characterized by progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. Pantothenate kinase-associated neurodegeneration (PKAN) is one of the most widespread NBIA subtypes. It is caused by mutations in the gene of pantothenate kinase 2 (PANK2) that result in dysfunction in PANK2 enzyme activity, with consequent deficiency of coenzyme A (CoA) biosynthesis, as well as low levels of essential metabolic intermediates such as 4′-phosphopantetheine, a necessary cofactor for essential cytosolic and mitochondrial proteins. Methods In this manuscript, we examined the therapeutic effectiveness of pantothenate, panthetine, antioxidants (vitamin E and omega 3) and mitochondrial function boosting supplements (L-carnitine and thiamine) in mutant PANK2 cells with residual expression levels. Results Commercial supplements, pantothenate, pantethine, vitamin E, omega 3, carnitine and thiamine were able to eliminate iron accumulation, increase PANK2, mtACP, and NFS1 expression levels and improve pathological alterations in mutant cells with residual PANK2 expression levels. Conclusion Our results suggest that several commercial compounds are indeed able to significantly correct the mutant phenotype in cellular models of PKAN. These compounds alone or in combinations are of common use in clinical practice and may be useful for the treatment of PKAN patients with residual enzyme expression levels. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02465-9.
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Affiliation(s)
- Mónica Álvarez-Córdoba
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Diana Reche-López
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Paula Cilleros-Holgado
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Marta Talaverón-Rey
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Irene Villalón-García
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Suleva Povea-Cabello
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Juan M Suárez-Rivero
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Alejandra Suárez-Carrillo
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Manuel Munuera-Cabeza
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - Rocío Piñero-Pérez
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain
| | - José A Sánchez-Alcázar
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red: Enfermedades Raras, Instituto de Salud Carlos III, 41013, Sevilla, Spain.
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Karissa P, Simpson T, Dawson SP, Low TY, Tay SH, Nordin FDA, Zain SM, Lee PY, Pung YF. Comparison Between Dichloroacetate and Phenylbutyrate Treatment for Pyruvate Dehydrogenase Deficiency. Br J Biomed Sci 2022; 79:10382. [PMID: 35996497 PMCID: PMC9302545 DOI: 10.3389/bjbs.2022.10382] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/27/2022] [Indexed: 11/13/2022]
Abstract
Pyruvate dehydrogenase (PDH) deficiency is caused by a number of pathogenic variants and the most common are found in the PDHA1 gene. The PDHA1 gene encodes one of the subunits of the PDH enzyme found in a carbohydrate metabolism pathway involved in energy production. Pathogenic variants of PDHA1 gene usually impact the α-subunit of PDH causing energy reduction. It potentially leads to increased mortality in sufferers. Potential treatments for this disease include dichloroacetate and phenylbutyrate, previously used for other diseases such as cancer and maple syrup urine disease. However, not much is known about their efficacy in treating PDH deficiency. Effective treatment for PDH deficiency is crucial as carbohydrate is needed in a healthy diet and rice is the staple food for a large portion of the Asian population. This review analysed the efficacy of dichloroacetate and phenylbutyrate as potential treatments for PDH deficiency caused by PDHA1 pathogenic variants. Based on the findings of this review, dichloroacetate will have an effect on most PDHA1 pathogenic variant and can act as a temporary treatment to reduce the lactic acidosis, a common symptom of PDH deficiency. Phenylbutyrate can only be used on patients with certain pathogenic variants (p.P221L, p.R234G, p.G249R, p.R349C, p.R349H) on the PDH protein. It is hoped that the review would provide an insight into these treatments and improve the quality of lives for patients with PDH deficiency.
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Affiliation(s)
- Patricia Karissa
- Division of Biomedical Science, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Malaysia
| | - Timothy Simpson
- Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Simon P Dawson
- Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Teck Yew Low
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Sook Hui Tay
- Division of Biomedical Science, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Malaysia
| | | | - Shamsul Mohd Zain
- Department of Pharmacology, Faculty of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - Pey Yee Lee
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Yuh-Fen Pung
- Division of Biomedical Science, Faculty of Science and Engineering, University of Nottingham Malaysia, Semenyih, Malaysia
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10
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Inui T, Wada Y, Shibuya M, Arai-Ichinoi N, Okubo Y, Endo W, Uchida T, Togashi N, Naito E, Haginoya K. Intravenous ketogenic diet therapy for neonatal-onset pyruvate dehydrogenase complex deficiency. Brain Dev 2022; 44:244-248. [PMID: 34863613 DOI: 10.1016/j.braindev.2021.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 11/03/2021] [Accepted: 11/17/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Pyruvate dehydrogenase complex (PDHC) deficiency is an inborn error of metabolism that causes lactic acidosis and neurodevelopmental changes. Five causative genes have been identified: PDHA1, PDHB, DLAT, DLD, and PDHX. Four neurological phenotypes have been reported: neonatal encephalopathy with lactic acidosis, non-progressive infantile encephalopathy, Leigh syndrome, and relapsing ataxia. Of these, neonatal encephalopathy has the worst mortality and morbidity and there is no effective treatment. SUBJECTS AND METHODS We studied two girls who were clinically diagnosed with PDHC deficiency as neonates; they were subsequently found to have PDHA1 mutations. The clinical diagnosis was based on white matter loss and a lateral ventricular septum on fetal MRI, spasticity of the lower extremities, and lactic acidosis worsening after birth. Intravenous ketogenic diets were started within 24 h after birth. The ketogenic ratio was increased until the blood lactate level was controlled, while monitoring for side effects. RESULTS In both cases, the lactic acidosis improved immediately with no apparent side effects. Both children had better developmental outcomes than previously reported cases; neither exhibited epilepsy. CONCLUSIONS Intravenous ketogenic diet therapy is a treatment option for neonatal-onset PDHC deficiency. Further studies are needed to optimize this therapy.
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Affiliation(s)
- Takehiko Inui
- Department of Pediatric Neurology, Miyagi Children's Hospital, Miyagi, Japan.
| | - Yoichi Wada
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Moriei Shibuya
- Department of Pediatric Neurology, Miyagi Children's Hospital, Miyagi, Japan
| | - Natsuko Arai-Ichinoi
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan; Department of Pediatrics, Nihon University, Tokyo, Japan
| | - Yukimune Okubo
- Department of Pediatric Neurology, Miyagi Children's Hospital, Miyagi, Japan
| | - Wakaba Endo
- Department of Pediatric Neurology, Miyagi Children's Hospital, Miyagi, Japan
| | - Toshihiko Uchida
- Department of Neonatology, Miyagi Children's Hospital, Miyagi, Japan
| | - Noriko Togashi
- Department of Pediatric Neurology, Miyagi Children's Hospital, Miyagi, Japan
| | - Etsuo Naito
- Department of Pediatrics, Japanese Red Cross Tokushima Hinomine Rehabilitation Center for People with Disabilities, Tokushima, Japan
| | - Kazuhiro Haginoya
- Department of Pediatric Neurology, Miyagi Children's Hospital, Miyagi, Japan
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11
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Warnecke A, Giesemann A. Embryology, Malformations, and Rare Diseases of the Cochlea. Laryngorhinootologie 2021; 100:S1-S43. [PMID: 34352899 PMCID: PMC8354575 DOI: 10.1055/a-1349-3824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Despite the low overall prevalence of individual rare diseases, cochlear
dysfunction leading to hearing loss represents a symptom in a large
proportion. The aim of this work was to provide a clear overview of rare
cochlear diseases, taking into account the embryonic development of the
cochlea and the systematic presentation of the different disorders. Although
rapid biotechnological and bioinformatic advances may facilitate the
diagnosis of a rare disease, an interdisciplinary exchange is often required
to raise the suspicion of a rare disease. It is important to recognize that
the phenotype of rare inner ear diseases can vary greatly not only in
non-syndromic but also in syndromic hearing disorders. Finally, it becomes
clear that the phenotype of the individual rare diseases cannot be
determined exclusively by classical genetics even in monogenetic
disorders.
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Affiliation(s)
- Athanasia Warnecke
- Klinik für Hals-, Nasen- und Ohrenheilkunde, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover.,Deutsche Forschungsgemeinschaft Exzellenzcluster"Hearing4all" - EXC 2177/1 - Project ID 390895286
| | - Anja Giesemann
- Institut für Neuroradiologie, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover
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12
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Pavlu-Pereira H, Lousa D, Tomé CS, Florindo C, Silva MJ, de Almeida IT, Leandro P, Rivera I, Vicente JB. Structural and functional impact of clinically relevant E1α variants causing pyruvate dehydrogenase complex deficiency. Biochimie 2021; 183:78-88. [PMID: 33588022 DOI: 10.1016/j.biochi.2021.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 01/19/2023]
Abstract
Pyruvate dehydrogenase complex (PDC) catalyzes the oxidative decarboxylation of pyruvate to acetyl-coenzyme A, hinging glycolysis and the tricarboxylic acid cycle. PDC deficiency, an inborn error of metabolism, has a broad phenotypic spectrum. Symptoms range from fatal lactic acidosis or progressive neuromuscular impairment in the neonatal period, to chronic neurodegeneration. Most disease-causing mutations in PDC deficiency affect the PDHA1 gene, encoding the α subunit of the PDC-E1 component. Detailed biophysical analysis of pathogenic protein variants is a challenging approach to support the design of therapies based on improving and correcting protein structure and function. Herein, we report the characterization of clinically relevant PDC-E1α variants identified in Portuguese PDC deficient patients. These variants bear amino acid substitutions in different structural regions of PDC-E1α. The structural and functional analyses of recombinant heterotetrameric (αα'ββ') PDC-E1 variants, combined with molecular dynamics (MD) simulations, show a limited impact of the amino acid changes on the conformational stability, apart from the increased propensity for aggregation of the p.R253G variant as compared to wild-type PDC-E1. However, all variants presented a functional impairment in terms of lower residual PDC-E1 enzymatic activity and ≈3-100 × lower affinity for the thiamine pyrophosphate (TPP) cofactor, in comparison with wild-type PDC-E1. MD simulations neatly showed generally decreased stability (increased flexibility) of all variants with respect to the WT heterotetramer, particularly in the TPP binding region. These results are discussed in light of disease severity of the patients bearing such mutations and highlight the difficulty of developing chaperone-based therapies for PDC deficiency.
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Affiliation(s)
- Hana Pavlu-Pereira
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Diana Lousa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Catarina S Tomé
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Cristina Florindo
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Maria João Silva
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Tavares de Almeida
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Paula Leandro
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
| | - Isabel Rivera
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
| | - João B Vicente
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
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13
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Jelinek BA, Moxley MA. Detailed evaluation of pyruvate dehydrogenase complex inhibition in simulated exercise conditions. Biophys J 2021; 120:936-949. [PMID: 33515599 DOI: 10.1016/j.bpj.2021.01.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/31/2020] [Accepted: 01/19/2021] [Indexed: 11/19/2022] Open
Abstract
The mammalian pyruvate dehydrogenase complex (PDC) is a mitochondrial multienzyme complex that connects glycolysis to the tricarboxylic acid cycle by catalyzing pyruvate oxidation to produce acetyl-CoA, NADH, and CO2. This reaction is required to aerobically utilize glucose, a preferred metabolic fuel, and is composed of three core enzymes: pyruvate dehydrogenase (E1), dihydrolipoyl transacetylase (E2), and dihydrolipoyl dehydrogenase (E3). The pyruvate-dehydrogenase-specific kinase (PDK) and pyruvate-dehydrogenase-specific phosphatase (PDP) are considered the main control mechanism of mammalian PDC activity. However, PDK and PDP activity are allosterically regulated by several effectors fully overlapping PDC substrates and products. This collection of positive and negative feedback mechanisms confounds simple predictions of relative PDC flux, especially when all effectors are dynamically modulated during metabolic states that exist in physiologically realistic conditions, such as exercise. Here, we provide, to our knowledge, the first globally fitted, pH-dependent kinetic model of the PDC accounting for the PDC core reaction because it is regulated by PDK, PDP, metal binding equilibria, and numerous allosteric effectors. The model was used to compute PDH regulatory complex flux as a function of previously determined metabolic conditions used to simulate exercise and demonstrates increased flux with exercise. Our model reveals that PDC flux in physiological conditions is primarily inhibited by product inhibition (∼60%), mostly NADH inhibition (∼30-50%), rather than phosphorylation cycle inhibition (∼40%), but the degree to which depends on the metabolic state and PDC tissue source.
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Affiliation(s)
- Bodhi A Jelinek
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska
| | - Michael A Moxley
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska.
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14
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Pavlu-Pereira H, Silva MJ, Florindo C, Sequeira S, Ferreira AC, Duarte S, Rodrigues AL, Janeiro P, Oliveira A, Gomes D, Bandeira A, Martins E, Gomes R, Soares S, Tavares de Almeida I, Vicente JB, Rivera I. Pyruvate dehydrogenase complex deficiency: updating the clinical, metabolic and mutational landscapes in a cohort of Portuguese patients. Orphanet J Rare Dis 2020; 15:298. [PMID: 33092611 PMCID: PMC7579914 DOI: 10.1186/s13023-020-01586-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 10/13/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The pyruvate dehydrogenase complex (PDC) catalyzes the irreversible decarboxylation of pyruvate into acetyl-CoA. PDC deficiency can be caused by alterations in any of the genes encoding its several subunits. The resulting phenotype, though very heterogeneous, mainly affects the central nervous system. The aim of this study is to describe and discuss the clinical, biochemical and genotypic information from thirteen PDC deficient patients, thus seeking to establish possible genotype-phenotype correlations. RESULTS The mutational spectrum showed that seven patients carry mutations in the PDHA1 gene encoding the E1α subunit, five patients carry mutations in the PDHX gene encoding the E3 binding protein, and the remaining patient carries mutations in the DLD gene encoding the E3 subunit. These data corroborate earlier reports describing PDHA1 mutations as the predominant cause of PDC deficiency but also reveal a notable prevalence of PDHX mutations among Portuguese patients, most of them carrying what seems to be a private mutation (p.R284X). The biochemical analyses revealed high lactate and pyruvate plasma levels whereas the lactate/pyruvate ratio was below 16; enzymatic activities, when compared to control values, indicated to be independent from the genotype and ranged from 8.5% to 30%, the latter being considered a cut-off value for primary PDC deficiency. Concerning the clinical features, all patients displayed psychomotor retardation/developmental delay, the severity of which seems to correlate with the type and localization of the mutation carried by the patient. The therapeutic options essentially include the administration of a ketogenic diet and supplementation with thiamine, although arginine aspartate intake revealed to be beneficial in some patients. Moreover, in silico analysis of the missense mutations present in this PDC deficient population allowed to envisage the molecular mechanism underlying these pathogenic variants. CONCLUSION The identification of the disease-causing mutations, together with the functional and structural characterization of the mutant protein variants, allow to obtain an insight on the severity of the clinical phenotype and the selection of the most appropriate therapy.
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Affiliation(s)
- Hana Pavlu-Pereira
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal
| | - Maria João Silva
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - Cristina Florindo
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal
| | - Sílvia Sequeira
- Department of Pediatrics, Hospital D. Estefânia, Lisbon, Portugal
| | | | - Sofia Duarte
- Department of Pediatrics, Hospital D. Estefânia, Lisbon, Portugal
| | | | - Patrícia Janeiro
- Department of Pediatrics, Hospital Santa Maria, Lisbon, Portugal
| | | | - Daniel Gomes
- Department of Medicine, Hospital Santa Maria, Lisbon, Portugal
| | - Anabela Bandeira
- Department of Pediatrics, Hospital Santo António, Porto, Portugal
| | | | - Roseli Gomes
- Department of Neuropediatrics, Hospital Pedro Hispano, Matosinhos, Portugal
| | - Sérgia Soares
- Department of Neuropediatrics, Hospital Pedro Hispano, Matosinhos, Portugal
| | - Isabel Tavares de Almeida
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - João B Vicente
- Instituto de Tecnologia Química e Biológica António Xavier, NOVA University of Lisbon, Av. da República (Estação Agronómica Nacional), 2780-157, Oeiras, Portugal.
| | - Isabel Rivera
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal.
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal.
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15
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Galosi S, Nardecchia F, Leuzzi V. Treatable Inherited Movement Disorders in Children: Spotlight on Clinical and Biochemical Features. Mov Disord Clin Pract 2020; 7:154-166. [PMID: 32071932 DOI: 10.1002/mdc3.12897] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 12/15/2019] [Accepted: 01/01/2020] [Indexed: 12/26/2022] Open
Abstract
Background About 80% of monogenic metabolic diseases causing movement disorders (MDs) emerges during the first 2 decades of life, and a number of these conditions offers the opportunity of a disease-modifying treatment. The implementation of enlarged neonatal screening programs and the impressive rapid increase of the identification of new conditions are enhancing our potential to recognize and treat several diseases causing MDs, changing their outcome and phenotypic spectrum. Methods and Findings A literature review of monogenic disorders causing MDs amenable to treatment was conducted focusing on early clinical signs and diagnostic biomarkers. A classification in 3 broad categories based on the therapeutic approach has been proposed. Some disorders result in irreversible neurotoxic lesions that can only be prevented if treated in a presymptomatic stage, and others present with a progressive neurological impairment that a timely diagnosis and treatment may reverse or improve. Some MDs are the result of the failure of intracellular energy supply or altered glucose transport. The treatment in these conditions includes vitamins or a metabolic shift from a carbohydrate to a fatty acid catabolism, respectively. Finally, a group of highly treatable MDs are the result of defects of neurotransmitter metabolism. In these disorders, the supplementation of precursors or mimetics of neurotransmitters can deeply change the disease natural history. Conclusions To prevent serious and irreversible neurological impairment, the diagnostic work-up of MDs in children should consider a number of clinical red flags and biomarkers denoting specifically treatable diseases.
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Affiliation(s)
- Serena Galosi
- Department of Human Neuroscience Sapienza University Rome Italy
| | | | - Vincenzo Leuzzi
- Department of Human Neuroscience Sapienza University Rome Italy
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16
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Abstract
OBJECTIVES To report 2 additional cases of pyruvate dehydrogenase complex deficiency with reversible deep gray matter lesions following initiation of ketogenic diet and to perform a literature review of serial imaging in patients with pyruvate dehydrogenase complex. METHODS Clinical data on 3 previously unpublished cases of patients with pyruvate dehydrogenase complex deficiency and with serial magnetic resonance imagings (MRIs) before and after institution of ketogenic diet were reported. A systematic literature review was performed to search for published cases of patients with confirmed pyruvate dehydrogenase complex deficiency who underwent serial MRIs. RESULTS The 3 subjects in this series demonstrated clinical improvement on ketogenic diet. Two subjects showed reversal of some brain lesions on repeat MRI following initiation of ketogenic diet. Of the 21 published cases with serial MRIs, 13 patients underwent some form of treatment, and of this smaller subset 4 patients had repeat MRIs that showed definitive improvement. In both our described cases and those published in the literature, improvement occurred in lesions in the basal ganglia. CONCLUSIONS In patients with pyruvate dehydrogenase complex deficiency, basal ganglia lesions on MRI are reversible with treatment in some cases and could serve as a biomarker for measuring response to treatment.
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Affiliation(s)
- Emily Shelkowitz
- Section of Genetics, Department of Pediatrics, University of Colorado, School of Medicine, Aurora, CO, USA
| | - Can Ficicioglu
- Division of Human Genetics, The Children's Hospital Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Nicholas Stence
- Department of Radiology, University of Colorado, School of Medicine, Aurora, CO, USA
| | - Johan Van Hove
- Section of Genetics, Department of Pediatrics, University of Colorado, School of Medicine, Aurora, CO, USA
| | - Austin Larson
- Section of Genetics, Department of Pediatrics, University of Colorado, School of Medicine, Aurora, CO, USA
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Abstract
Primary mitochondrial disorders are a group of clinically variable and heterogeneous inborn errors of metabolism (IEMs), resulting from defects in cellular energy, and can affect every organ system of the body. Clinical presentations vary and may include symptoms of fatigue, skeletal muscle weakness, exercise intolerance, short stature, failure to thrive, blindness, ptosis and ophthalmoplegia, nystagmus, hearing loss, hypoglycemia, diabetes mellitus, learning difficulties, intellectual disability, seizures, stroke-like episodes, spasticity, dystonia, hypotonia, pain, neuropsychiatric symptoms, gastrointestinal reflux, dysmotility, gastrointestinal pseudo-obstruction, cardiomyopathy, cardiac conduction defects, and other endocrine, renal, cardiac, and liver problems. Most phenotypic manifestations are multi-systemic, with presentations varying at different age of onset and may show great variability within members of the same family; making these truly complex IEMs. Most primary mitochondrial diseases are autosomal recessive (AR); but maternally-inherited [from mitochondrial (mt) DNA], autosomal dominant and X-linked inheritance are also known. Mitochondria are unique energy-generating cellular organelles, geared for survival and contain their own unique genetic coding material, a circular piece of mtDNA about 16,000 base pairs in size. Additional nuclear (n)DNA encoded genes maintain mitochondrial biogenesis by supervising mtDNA replication, repair and synthesis, which is modified during increased energy demands or physiological stress. Despite our growing knowledge of the hundreds of genetic etiologies for this group of disorders, diagnosis can also remain elusive due to unique aspects of mitochondrial genetics. Though cure and FDA-approved therapies currently elude these IEMs, and current suggested therapies which include nutritional supplements and vitamins are of questionable efficacy; multi-center, international clinical trials are in progress for primary mitochondrial disorders.
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Affiliation(s)
- Shibani Kanungo
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, Michigan, USA
| | - Jacob Morton
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, Michigan, USA
| | - Mekala Neelakantan
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, Michigan, USA
| | - Kevin Ching
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, Michigan, USA
| | - Jasmine Saeedian
- Department of Pediatric and Adolescent Medicine, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, Michigan, USA
| | - Amy Goldstein
- Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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18
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Jauhari P, Sankhyan N, Vyas S, Singhi P. Thiamine Responsive Pyruvate Dehydrogenase Complex Deficiency: A Potentially Treatable Cause of Leigh's Disease. J Pediatr Neurosci 2017; 12:265-267. [PMID: 29204204 PMCID: PMC5696666 DOI: 10.4103/jpn.jpn_191_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Pyruvate dehydrogenase complex (PDHC) deficiency is a rare metabolic disorder that affects tissues with high energy demand such as the central nervous system. The clinico-radiological phenotype of Leigh's disease is one of its common presentations. We present a 9-month-old boy with rapidly progressive infantile Leigh's disease. PDHA1 gene sequencing revealed a pathological homozygous missense mutation c.131A>G or p.H44R in exon 3 consistent with PDHC deficiency. H44R is among the five mutations (H44R, R88S, G89S, R263G, and V389fs) in E1α subunit that is thiamine-responsive. The child was initiated on thiamine, riboflavin, carnitine, coenzyme Q, and sodium benzoate supplementation. Mild recovery was noted at 6 months follow up as no further episodes of encephalopathy occurred. Thereafter, the child was treated with Ketogenic diet which resulted in increased levels of activity and alertness. Despite an improving course, the child had a sudden unexpected death at the age of 21 months.
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Affiliation(s)
- Prashant Jauhari
- Department of Pediatrics, Pediatric Neurology and Neurodevelopment Unit, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Naveen Sankhyan
- Department of Pediatrics, Pediatric Neurology and Neurodevelopment Unit, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Sameer Vyas
- Department of Radiodiagnosis, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Pratibha Singhi
- Department of Pediatrics, Pediatric Neurology and Neurodevelopment Unit, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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19
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Pliss L, Jatania U, Patel MS. Beneficial effect of feeding a ketogenic diet to mothers on brain development in their progeny with a murine model of pyruvate dehydrogenase complex deficiency. Mol Genet Metab Rep 2016; 7:78-86. [PMID: 27331005 PMCID: PMC4901178 DOI: 10.1016/j.ymgmr.2016.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 03/31/2016] [Accepted: 03/31/2016] [Indexed: 12/12/2022] Open
Abstract
Pyruvate dehydrogenase complex (PDC) deficiency is a major inborn error of oxidative metabolism of pyruvate in the mitochondria causing congenital lactic acidosis and primarily structural and functional abnormalities of the central nervous system. To provide an alternate source of acetyl-CoA derived from ketone bodies to the developing brain, a formula high in fat content is widely employed as a treatment. In the present study we investigated efficacy of a high-fat diet given to mothers during pregnancy and lactation on lessening of the impact of PDC deficiency on brain development in PDC-deficient female progeny. Methods A murine model of systemic PDC deficiency by interrupting the X-linked Pdha1 gene was employed in this study. Results Maternal consumption of a high-fat diet during pregnancy and lactation had no effect on number of live-birth, body growth, tissue PDC activity levels, as well as the in vitro rates of glucose oxidation and fatty acid biosynthesis by the developing brain of PDC-deficient female offspring during the postnatal age 35 days, as compared to the PDC-deficient progeny born to dams on a chow diet. Interestingly, brain weight was normalized in PDC-deficient progeny of high fat-fed mothers with improvement in impairment in brain structure deficit whereas brain weight was significantly decreased and was associated with greater cerebral structural defects in progeny of chow-fed mothers as compared to control progeny of mothers fed either a chow or high fat diet. Conclusion The findings provide for the first time experimental support for beneficial effects of a ketogenic diet during the prenatal and early postnatal periods on the brain development of PDC-deficient mammalian progeny.
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Key Words
- Brain development
- E18, embryonic day 18
- Glucose metabolism
- HF, high fat
- High fat diet
- LC, laboratory chow
- Mouse model
- P15, postnatal day 15
- PDC, pyruvate dehydrogenase complex
- PDH, pyruvate dehydrogenase
- PDHA1, human gene that encodes α subunit of PDH
- Pdha1, murine orthologue of PDHA1
- Prenatal treatment
- Pyruvate dehydrogenase complex deficiency
- flox8, Pdha1 floxed allele
- wt, wild-type Pdha1 allele
- Δex8, Pdha1 null allele
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Affiliation(s)
- Lioudmila Pliss
- Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - Urvi Jatania
- Department of Exercise and Nutrition, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY 14214, USA
| | - Mulchand S. Patel
- Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA
- Corresponding author at: Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 140 Farber Hall, Buffalo, NY 14214, USA.Department of BiochemistryJacobs School of Medicine and Biomedical SciencesUniversity at Buffalo140 Farber HallBuffaloNY14214USA
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Castiglioni C, Verrigni D, Okuma C, Diaz A, Alvarez K, Rizza T, Carrozzo R, Bertini E, Miranda M. Pyruvate dehydrogenase deficiency presenting as isolated paroxysmal exercise induced dystonia successfully reversed with thiamine supplementation. Case report and mini-review. Eur J Paediatr Neurol 2015; 19:497-503. [PMID: 26008863 DOI: 10.1016/j.ejpn.2015.04.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/10/2015] [Accepted: 04/29/2015] [Indexed: 01/29/2023]
Abstract
BACKGROUND Pyruvate dehydrogenase (PDH) deficiency is a disorder of energy metabolism with variable clinical presentations, ranging from severe infantile lactic acidosis to milder chronic neurological disorders. The spectrum of clinical manifestations is continuously expanding. METHODS AND RESULTS We report on a 19-year-old intelligent female with PDH deficiency caused by a Leu216Ser mutation in PDHA1. She presented with recurrent hemidystonic attacks, triggered by prolonged walking or running, as the unique clinical manifestation that manifested since childhood. Laboratory workup and neuroimages were initially normal but bilateral globus pallidum involvement appeared later on brain MRI. Dystonia completely remitted after high doses of thiamine, remaining free of symptoms after 3 years of follow up. We reviewed the literature for similar observations. CONCLUSIONS Dystonia precipitated by exercise may be the only symptom of a PDH deficiency, and the hallmark of the disease as high serum lactate or bilateral striatal necrosis at neuroimaging may be absent. A high index of suspicion and follow up is necessary for diagnosis. The clinical presentation of this patient meets the criteria for a Paroxysmal Exercise induced Dystonia, leading us to add this entity as another potential etiology for this type of paroxysmal dyskinesia, which is besides a treatable condition that responds to thiamine supplementation.
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Affiliation(s)
- Claudia Castiglioni
- Unit of Neurology, Dept. of Pediatrics and Dept. of Neurology, Clínica las Condes, Santiago, Chile.
| | - Daniela Verrigni
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Hospital IRCCS, Rome, Italy
| | - Cecilia Okuma
- Dept. of Radiology, Clínica las Condes, Santiago, Chile
| | - Alejandra Diaz
- National Institute of Rehabilitation, INRPAC, Santiago, Chile
| | - Karin Alvarez
- Laboratory of Molecular Genetics and Oncology, Clínica las Condes, Santiago, Chile
| | - Teresa Rizza
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Hospital IRCCS, Rome, Italy
| | - Rosalba Carrozzo
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Hospital IRCCS, Rome, Italy
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Hospital IRCCS, Rome, Italy
| | - Marcelo Miranda
- Unit of Neurology, Dept. of Pediatrics and Dept. of Neurology, Clínica las Condes, Santiago, Chile
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21
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Sperl W, Fleuren L, Freisinger P, Haack TB, Ribes A, Feichtinger RG, Rodenburg RJ, Zimmermann FA, Koch J, Rivera I, Prokisch H, Smeitink JA, Mayr JA. The spectrum of pyruvate oxidation defects in the diagnosis of mitochondrial disorders. J Inherit Metab Dis 2015; 38:391-403. [PMID: 25526709 DOI: 10.1007/s10545-014-9787-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 10/20/2014] [Accepted: 10/23/2014] [Indexed: 10/24/2022]
Abstract
Pyruvate oxidation defects (PODs) are among the most frequent causes of deficiencies in the mitochondrial energy metabolism and represent a substantial subset of classical mitochondrial diseases. PODs are not only caused by deficiency of subunits of the pyruvate dehydrogenase complex (PDHC) but also by various disorders recently described in the whole pyruvate oxidation route including cofactors, regulation of PDHC and the mitochondrial pyruvate carrier. Our own patients from 2000 to July 2014 and patients identified by a systematic survey of the literature from 1970 to July 2014 with a pyruvate oxidation disorder and a genetically proven defect were included in the study (n=628). Of these defects 74.2% (n=466) belong to PDHC subunits, 24.5% (n=154) to cofactors, 0.5% (n=3) to PDHC regulation and 0.8% (n=5) to mitochondrial pyruvate import. PODs are underestimated in the field of mitochondrial diseases because not all diagnostic centres include biochemical investigations of PDHC in their routine analysis. Cofactor and transport defects can be missed, if pyruvate oxidation is not measured in intact mitochondria routinely. Furthermore deficiency of the X-chromosomal PDHA1 can be biochemically missed depending on the X-inactivation pattern. This is reflected by an increasing number of patients diagnosed recently by genetic high throughput screening approaches. PDHC deficiency including regulation and import affect mainly the glucose dependent central and peripheral nervous system and skeletal muscle. PODs with combined enzyme defects affect also other organs like heart, lung and liver. The spectrum of clinical presentation of PODs is still expanding. PODs are a therapeutically interesting group of mitochondrial diseases since some can be bypassed by ketogenic diet or treated by cofactor supplementation. PDHC kinase inhibition, chaperone therapy and PGC1α stimulation is still a matter of further investigations.
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Affiliation(s)
- Wolfgang Sperl
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, Salzburg, 5020, Austria,
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22
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Abstract
Thiamine, in the form of thiamine pyrophosphate, is a cofactor for a number of enzymes which play important roles in energy metabolism. Although dietary thiamine deficiency states have long been recognised, it is only relatively recently that inherited defects in thiamine uptake, activation and the attachment of the active cofactor to target enzymes have been described, and the underlying genetic defects identified. Thiamine is transported into cells by two carriers, THTR1 and THTR2, and deficiency of these results in thiamine-responsive megaloblastic anaemia and biotin-responsive basal ganglia disease respectively. Defective synthesis of thiamine pyrophosphate has been found in a small number of patients with episodic ataxia, delayed development and dystonia, while impaired transport of thiamine pyrophosphate into the mitochondrion is associated with Amish lethal microcephaly in most cases. In addition to defects in thiamine uptake and metabolism, patients with pyruvate dehydrogenase deficiency and maple syrup urine disease have been described who have a significant clinical and/or biochemical response to thiamine supplementation. In these patients, an intrinsic structural defect in the target enzymes reduces binding of the cofactor and this can be overcome at high concentrations. In most cases, the clinical and biochemical abnormalities in these conditions are relatively non-specific, and the range of recognised presentations is increasing rapidly at present as new patients are identified, often by genome sequencing. These conditions highlight the value of a trial of thiamine supplementation in patients whose clinical presentation falls within the spectrum of documented cases.
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Affiliation(s)
- Garry Brown
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK,
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23
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van Dongen S, Brown RM, Brown GK, Thorburn DR, Boneh A. Thiamine-Responsive and Non-responsive Patients with PDHC-E1 Deficiency: A Retrospective Assessment. JIMD Rep 2015; 15:13-27. [PMID: 24718837 DOI: 10.1007/8904_2014_293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/03/2014] [Accepted: 01/09/2014] [Indexed: 03/29/2023] Open
Abstract
UNLABELLED Pyruvate dehydrogenase complex (PDHC) deficiency is a disorder of energy metabolism that leads to a range of clinical manifestations. We sought to characterise clinical manifestations and biochemical, neuroimaging and molecular findings in thiamine-responsive and nonresponsive PDHC-deficient patients and to identify potential pitfalls in the diagnosis of PDHC deficiency. We retrospectively reviewed all medical records of all PDHC-deficient patients (n = 19; all had PDHA1 gene mutations) and one patient with severe PDHC deficiency secondary to 3-hydroxyisobutyryl-CoA hydrolase deficiency managed at our centre between 1982 and 2012. Responsiveness to thiamine was based on clinical parameters. Seventeen patients received thiamine treatment: eight did not respond, four showed sustained response and the others responded temporarily/questionably. Sustained response was noted at thiamine doses >400 mg/day. Age at presentation was 0-6 and 12-27 months in the nonresponsive (n = 8) and responsive (n = 4) patients, respectively. Corpus callosum abnormalities were noted in 4/8 nonresponsive patients. Basal ganglia involvement (consistent with Leigh disease) was found in four patients (including 2/4 thiamine-responsive patients). Diagnosis through mutation analysis was more sensitive and specific than through enzymatic analysis. We conclude that patients presenting at age >12 months with relapsing ataxia and possibly Leigh syndrome are more likely to be thiamine responsive than those presenting with neonatal lactic acidosis and corpus callosum abnormalities. However, this distinction is equivocal and treatment with thiamine (>400 mg/day) should be commenced on all patients suspected of having PDHC deficiency. Mutation analysis is the preferable first-line diagnostic test to avoid missing thiamine-responsive patients and misdiagnosing patients with secondary PDHC deficiency. SHORT SUMMARY Thiamine responsiveness is more likely in patients presenting at age >12 months with relapsing ataxia and possibly Leigh syndrome than in those presenting with neonatal lactic acidosis and corpus callosum abnormalities. Thiamine doses >400 mg/day are required for sustained response. Mutation analysis is more sensitive and specific than enzymatic analysis as a first-line diagnostic test.
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Singhi P, De Meirleir L, Lissens W, Singhi S, Saini AG. Pyruvate dehydrogenase-e1α deficiency presenting as recurrent demyelination: an unusual presentation and a novel mutation. JIMD Rep 2013; 10:107-11. [PMID: 23430811 DOI: 10.1007/8904_2012_211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 12/26/2012] [Accepted: 12/28/2012] [Indexed: 12/13/2022] Open
Abstract
The nucleus-encoded mitochondrial pyruvate dehydrogenase enzyme complex plays key roles in cellular energy metabolism and acid-base equilibrium. Pyruvate dehydrogenase complex deficiency is due to loss-of-function mutation in one of the five component enzymes, most commonly E1α-subunit. The common clinical presentation ranges from fatal infantile lactic acidosis in newborns to chronic neurological dysfunction. We describe here an unusual presentation of E1α-subunit deficiency presenting as recurrent demyelination, Guillain-Barré syndrome-like demyelinating polyneuropathy at the onset, and ophthalmoplegia in a young infant. The clinical phenotype of the mutation in the patient was unique as compared to the previous reported cases of pyruvate dehydrogenase deficiency. The mother was found to be a mosaic carrier of the mutation. This phenotypic variability of pyruvate dehydrogenase complex deficiency and early suspicion of its unusual neurological manifestations is highlighted. Thiamine and ketogenic diet can be helpful.
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Affiliation(s)
- Pratibha Singhi
- Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India,
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25
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Abstract
Pyruvate dehydrogenase and pyruvate carboxylase deficiency are the most common disorders in pyruvate metabolism. Diagnosis is made by enzymatic and DNA analysis after basic biochemical tests in plasma, urine, and CSF. Pyruvate dehydrogenase has three main subunits, an additional E3-binding protein and two complex regulatory enzymes. Most frequent are deficiencies in PDH-E1α. There is a spectrum of clinical presentations in E1α deficiency, ranging in boys from severe neonatal lactic acidosis, Leigh encephalopathy, to later onset of neurological disease such as intermittent ataxia or dystonia. Females tend to have a more uniform presentation resembling nonprogressive cerebral palsy. Neuroradiological abnormalities such as corpus callosum agenesis are seen more frequently in girls, basal ganglia and midbrain disturbances in boys. Deficiencies in the other subunits have also been described, but in a smaller number of patients. Pyruvate carboxylase deficiency has three clinical phenotypes. The infantile type is characterized mainly by severe developmental delay, failure to thrive, and seizures. The second type is characterized by neonatal onset of severe lactic acidosis with rigidity and hypokinesia. A third form is rarer with intermittent episodes of lactic acidosis and ketoacidosis. Neuroradiological findings such as cystic periventricular leukomalacia have been described.
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26
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DeBrosse SD, Okajima K, Zhang S, Nakouzi G, Schmotzer CL, Lusk-Kopp M, Frohnapfel MB, Grahame G, Kerr DS. Spectrum of neurological and survival outcomes in pyruvate dehydrogenase complex (PDC) deficiency: lack of correlation with genotype. Mol Genet Metab 2012; 107:394-402. [PMID: 23021068 DOI: 10.1016/j.ymgme.2012.09.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Revised: 08/31/2012] [Accepted: 09/01/2012] [Indexed: 10/27/2022]
Abstract
Pyruvate dehydrogenase complex (PDC) deficiency is a relatively common mitochondrial disorder that primarily presents with neurological manifestations and lactic acidemia. We analyzed the clinical outcomes and neurological features of 59 consented symptomatic subjects (27 M, 32 F), who were confirmed to have PDC deficiency with defined mutations in one of the genes of PDC (PDHA1, n = 53; PDHB, n = 4; DLAT, n = 2), including 47 different mutations, of which 22 were novel, and for whom clinical records and/or structured interviews were obtained. 39% of these subjects (23/59) have died. Of these, 91% (21/23) died before age 4 years, 61% (14/23) before 1 year, and 43% (10/23) before 3 months. 56% of males died compared with 25% of females. Causes of death included severe lactic acidosis, respiratory failure, and infection. In subjects surviving past 6 months, a broad range of intellectual outcomes was observed. Of 42 subjects whose intellectual abilities were professionally evaluated, 19% had normal or borderline intellectual ability (CQ/IQ ≥ 70), 10% had mild intellectual disability (ID) (CQ/IQ 55-69), 17% had moderate ID (CQ/IQ 40-54), 24% had severe ID (CQ/IQ 25-39) and 33% had profound ID (CQ/IQ<25). Assessment by parents was comparable. Of 10 subjects who reached age 12 years, 9 had had professional IQ assessments, and only 4 had IQs ≥ 70 (only 2 of these 4 had assessments after age 12 years). The average outcome for females was severe-to-profound ID, whereas that of males was mild-to-moderate ID. Of subjects for whom specific neurological data were available, the majority had hypotonia (89%), and hypertonia or mixed hyper-/hypotonia (49%) were common. Seizures (57%), microcephaly (49%), and structural brain abnormalities including ventriculomegaly (67%) and agenesis, dysgenesis, or hypoplasia of the corpus callosum (55%) were common. Leigh syndrome was found in only 35%. Structural brain abnormalities were more common in females, and Leigh syndrome was more common in males. In a subgroup of 16 ambulatory subjects >3.5 years in whom balance was evaluated, ataxia was found in 13. Peripheral neuropathy was documented in 2 cases but not objectively evaluated in most subjects. Outcomes of this population with genetically confirmed PDC deficiency are heterogeneous and not distinctive. Correlations between specific genotypes and outcomes were not established. Although more females survive, related to the prevalence of X-linked PDHA1 mutations, symptomatic surviving females are generally more severely impaired cognitively and have a different pattern of neurological impairment compared to males. Neonatal or infant onset of symptoms was associated with poor outcomes. Males with PDHA1 mutations and low fibroblast PDC activity were less likely to survive beyond infancy. Recurrence rate in siblings of subjects with PDHA1 mutation was less than 5%. Paradoxically, in this retrospective review, potential factors considered possibly relevant to development, such as in vitro PDC activity, specific mutations, use of ketogenic diets, supplements, or medications, were generally not confirmed to be significantly correlated with objective outcomes of survival or neuro-cognitive function. Therefore, the basis of variability of these outcomes remains largely undetermined.
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27
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Patel KP, O’Brien TW, Subramony SH, Shuster J, Stacpoole PW. The spectrum of pyruvate dehydrogenase complex deficiency: clinical, biochemical and genetic features in 371 patients. Mol Genet Metab 2012; 106:385-94. [PMID: 22896851 PMCID: PMC4003492 DOI: 10.1016/j.ymgme.2012.03.017] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CONTEXT Pyruvate dehydrogenase complex (PDC) deficiency is a genetic mitochondrial disorder commonly associated with lactic acidosis, progressive neurological and neuromuscular degeneration and, usually, death during childhood. There has been no recent comprehensive analysis of the natural history and clinical course of this disease. OBJECTIVE We reviewed 371 cases of PDC deficiency, published between 1970 and 2010, that involved defects in subunits E1α and E1β and components E1, E2, E3 and the E3 binding protein of the complex. DATA SOURCES AND EXTRACTION English language peer-reviewed publications were identified, primarily by using PubMed and Google Scholar search engines. RESULTS Neurodevelopmental delay and hypotonia were the commonest clinical signs of PDC deficiency. Structural brain abnormalities frequently included ventriculomegaly, dysgenesis of the corpus callosum and neuroimaging findings typical of Leigh syndrome. Neither gender nor any clinical or neuroimaging feature differentiated the various biochemical etiologies of the disease. Patients who died were younger, presented clinically earlier and had higher blood lactate levels and lower residual enzyme activities than subjects who were still alive at the time of reporting. Survival bore no relationship to the underlying biochemical or genetic abnormality or to gender. CONCLUSIONS Although the clinical spectrum of PDC deficiency is broad, the dominant clinical phenotype includes presentation during the first year of life; neurological and neuromuscular degeneration; structural lesions revealed by neuroimaging; lactic acidosis and a blood lactate:pyruvate ratio ≤ 20.
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Affiliation(s)
- Kavi P. Patel
- Department of Medicine (Division of Endocrinology, Metabolism and
Diabetes), College of Medicine, University of Florida, Gainesville, FL 32611,
USA
| | - Thomas W. O’Brien
- Department of Biochemistry and Molecular Biology, College of
Medicine, University of Florida, Gainesville, FL 32611, USA
| | | | - Jonathan Shuster
- Department of Epidemiology and Health Policy Research, College of
Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Peter W. Stacpoole
- Department of Medicine (Division of Endocrinology, Metabolism and
Diabetes), College of Medicine, University of Florida, Gainesville, FL 32611,
USA
- Department of Biochemistry and Molecular Biology, College of
Medicine, University of Florida, Gainesville, FL 32611, USA
- Corresponding author at: UF College of Medicine, 1600 SW
Archer Road M2-238, P.O. Box 100226, Gainesville, FL 32610, USA. Fax: +1
352 273 9013. (P.W. Stacpoole)
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28
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Patel KP, O'Brien TW, Subramony SH, Shuster J, Stacpoole PW. The spectrum of pyruvate dehydrogenase complex deficiency: clinical, biochemical and genetic features in 371 patients. Mol Genet Metab 2012; 105:34-43. [PMID: 22079328 PMCID: PMC3754811 DOI: 10.1016/j.ymgme.2011.09.032] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 09/27/2011] [Accepted: 09/27/2011] [Indexed: 01/01/2023]
Abstract
CONTEXT Pyruvate dehydrogenase complex (PDC) deficiency is a genetic mitochondrial disorder commonly associated with lactic acidosis, progressive neurological and neuromuscular degeneration and, usually, death during childhood. There has been no recent comprehensive analysis of the natural history and clinical course of this disease. OBJECTIVE We reviewed 371 cases of PDC deficiency, published between 1970 and 2010, that involved defects in subunits E1α and E1β and components E1, E2, E3 and the E3 binding protein of the complex. DATA SOURCES AND EXTRACTION English language peer-reviewed publications were identified, primarily by using PubMed and Google Scholar search engines. RESULTS Neurodevelopmental delay and hypotonia were the commonest clinical signs of PDC deficiency. Structural brain abnormalities frequently included ventriculomegaly, dysgenesis of the corpus callosum and neuroimaging findings typical of Leigh syndrome. Neither gender nor any clinical or neuroimaging feature differentiated the various biochemical etiologies of the disease. Patients who died were younger, presented clinically earlier and had higher blood lactate levels and lower residual enzyme activities than subjects who were still alive at the time of reporting. Survival bore no relationship to the underlying biochemical or genetic abnormality or to gender. CONCLUSIONS Although the clinical spectrum of PDC deficiency is broad, the dominant clinical phenotype includes presentation during the first year of life; neurological and neuromuscular degeneration; structural lesions revealed by neuroimaging; lactic acidosis and a blood lactate:pyruvate ratio ≤20.
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Affiliation(s)
- Kavi P. Patel
- Department of Medicine (Division of Endocrinology and Metabolism), College of Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Thomas W. O'Brien
- Department of Biochemistry and Molecular Biology College of Medicine, University of Florida, Gainesville, FL, 32611, USA
| | | | - Jonathan Shuster
- Epidemiology and Health Policy Research College of Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Peter W. Stacpoole
- Department of Medicine (Division of Endocrinology and Metabolism), College of Medicine, University of Florida, Gainesville, FL, 32611, USA
- Department of Biochemistry and Molecular Biology College of Medicine, University of Florida, Gainesville, FL, 32611, USA
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29
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Abstract
Alzheimer's disease (AD) is the most common form of dementia in elderly individuals and is associated with progressive neurodegeneration of the human neocortex. Thiamine levels and the activity of thiamine-dependent enzymes are reduced in the brains and peripheral tissues of patients with AD. Genetic studies have provided the opportunity to determine what proteins link thiamine to AD pathology (ie, transketolase, apolipoprotein E, α-1-antitrypsin, pyruvate dehydrogenase complex, p53, glycogen synthetase kinase-3β, c-Fos gene, the Sp1 promoter gene, and the poly(ADP-ribosyl) polymerase-1 gene). We reviewed the association between histopathogenesis and neurotransmitters to understand the relationship between thiamine and AD pathology. Oral thiamine trials have been shown to improve the cognitive function of patients with AD; however, absorption of thiamine is poor in elderly individuals. In the early stage of thiamine-deficient encephalopathy (Wernicke's encephalopathy), however, parental thiamine has been used successfully. Therefore, further studies are needed to determine the benefits of using parental thiamine as a treatment for AD.
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30
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Abstract
Mitochondrial dysfunction has been linked to a wide range of degenerative and metabolic diseases, cancer, and aging. All these clinical manifestations arise from the central role of bioenergetics in cell biology. Although genetic therapies are maturing as the rules of bioenergetic genetics are clarified, metabolic therapies have been ineffectual. This failure results from our limited appreciation of the role of bioenergetics as the interface between the environment and the cell. A systems approach, which, ironically, was first successfully applied over 80 years ago with the introduction of the ketogenic diet, is required. Analysis of the many ways that a shift from carbohydrate glycolytic metabolism to fatty acid and ketone oxidative metabolism may modulate metabolism, signal transduction pathways, and the epigenome gives us an appreciation of the ketogenic diet and the potential for bioenergetic therapeutics.
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Affiliation(s)
- Douglas C Wallace
- Center for Molecular and Mitochondrial Medicine and Genetics and Departments of Biological Chemistry, Ecology and Evolutionary Biology, and Pediatrics, University of California at Irvine, Irvine, California 92697-3940, USA.
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31
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Abstract
Reductions in brain glucose metabolism and increased oxidative stress invariably occur in Alzheimer's disease (AD) and thiamine (vitamin B1) deficiency. Both conditions cause irreversible cognitive impairment; their behavioral consequences overlap but are not identical. Thiamine-dependent processes are critical in glucose metabolism, and recent studies implicate thiamine in oxidative stress, protein processing, peroxisomal function, and gene expression. The activities of thiamine-dependent enzymes are characteristically diminished in AD, and the reductions in autopsy AD brain correlate highly with the extent of dementia in the preagonal state. Abnormalities in thiamine-dependent processes can be plausibly linked to the pathology of AD. Seemingly paradoxical properties of thiamine-dependent processes may underlie their relation to the pathophysiology of AD: Reduction of thiamine-dependent processes increase oxidative stress. Thiamine can act as a free radical scavenger. Thiamine-dependent mitochondrial dehydrogenase complexes produce oxygen free radicals and are sensitive to oxidative stress. Genetic disorders of thiamine metabolism that lead to neurological disease can be treated with large doses of thiamine. Although thiamine itself has not shown dramatic benefits in AD patients, the available data is scanty. Adding thiamine or more absorbable forms of thiamine to tested treatments for the abnormality in glucose metabolism in AD may increase their efficacy.
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Affiliation(s)
- Gary E Gibson
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, Burke Medical Research Institute, White Plains, New York 10605, USA.
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32
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Lee EH, Ahn MS, Hwang JS, Ryu KH, Kim SJ, Kim SH. A Korean female patient with thiamine-responsive pyruvate dehydrogenase complex deficiency due to a novel point mutation (Y161C)in the PDHA1 gene. J Korean Med Sci 2006; 21:800-4. [PMID: 17043409 PMCID: PMC2721986 DOI: 10.3346/jkms.2006.21.5.800] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Pyruvate dehydrogenase complex (PDHC) deficiency is mostly due to mutations in the X-linked E1alpha subunit gene (PDHA1). Some of the patients with PDHC deficiency showed clinical improvements with thiamine treatment. We report the results of biochemical and molecular analysis in a female patient with lactic acidemia. The PDHC activity was assayed at different concentrations of thiamine pyrophosphate (TPP). The PDHC activity showed null activity at low TPP concentration (1 x 10(-3) mM), but significantly increased at a high TPP concentration (1 mM). Sequencing analysis of PDHA1 gene of the patient revealed a substitution of cysteine for tyrosine at position 161 (Y161C). Thiamine treatment resulted in reduction of the patient's serum lactate concentration and dramatic clinical improvement. Biochemical, molecular, and clinical data suggest that this patient has a thiamine-responsive PDHC deficiency due to a novel mutation, Y161C. Therefore, to detect the thiamine responsiveness it is necessary to measure activities of PDHC not only at high but also at low concentration of TPP.
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Affiliation(s)
- Eun-Ha Lee
- Department of Pediatrics and Research Laboratory for Human Mitochondrial Disorders, Ajou University School of Medicine, Suwon, Korea
| | - Mi-Sun Ahn
- Department of Pediatrics and Research Laboratory for Human Mitochondrial Disorders, Ajou University School of Medicine, Suwon, Korea
| | - Jin-Soon Hwang
- Department of Pediatrics and Research Laboratory for Human Mitochondrial Disorders, Ajou University School of Medicine, Suwon, Korea
| | - Kyung-Hwa Ryu
- Department of Pediatrics and Research Laboratory for Human Mitochondrial Disorders, Ajou University School of Medicine, Suwon, Korea
| | - Sun-Jun Kim
- Department of Pediatrics, Chonbuk National University Medical School, Jeonju, Korea
| | - Sung-Hwan Kim
- Department of Pediatrics and Research Laboratory for Human Mitochondrial Disorders, Ajou University School of Medicine, Suwon, Korea
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33
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Debray FG, Lambert M, Vanasse M, Decarie JC, Cameron J, Levandovskiy V, Robinson BH, Mitchell GA. Intermittent peripheral weakness as the presenting feature of pyruvate dehydrogenase deficiency. Eur J Pediatr 2006; 165:462-6. [PMID: 16552546 DOI: 10.1007/s00431-006-0104-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 01/22/2006] [Accepted: 01/24/2006] [Indexed: 10/24/2022]
Abstract
Two unrelated children presenting with episodic isolated peripheral weakness were found to have pyruvate dehydrogenase (PDH) deficiency (OMIM 312170) due to previously undescribed mutations (Pro250Thr, Arg88Cys) in the gene for the E1alpha subunit (PDHA1). Taken in context with the literature, these patients suggest that acute weakness initially resembling Guillain-Barré syndrome is a potentially reversible and probably underdiagnosed manifestation of PDH deficiency and that peripheral nerve function should be evaluated in PDH-deficient patients.
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Affiliation(s)
- Francois-G Debray
- Division of Medical Genetics, CHU Sainte-Justine, Université de Montréal, 3175 Côte Sainte-Catherine, Montreal, Québec, H3T 1C5, Canada
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Willemsen M, Rodenburg RJT, Teszas A, van den Heuvel L, Kosztolanyi G, Morava E. Females with PDHA1 gene mutations: a diagnostic challenge. Mitochondrion 2006; 6:155-9. [PMID: 16713755 DOI: 10.1016/j.mito.2006.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Revised: 02/28/2006] [Accepted: 03/06/2006] [Indexed: 10/24/2022]
Abstract
Biochemical analysis was performed in muscle tissue and in fibroblasts of four unrelated females consecutively diagnosed with a 'de novo' point mutation in the PDHA1 gene. Pyruvate dehydrogenase E1 subunit deficiency was confirmed in the muscle sample of all patients, however, in three out of four cases the activity of the pyruvate dehydrogenase complex in fibroblasts showed a normal activity. A skewed inactivation was confirmed of the maternal X chromosome in fibroblasts in all children. Due to the possibility of a skewed X inactivation pattern enzyme measurements in fibroblasts are not always reliable for the diagnosis of a PDHc defect in females. Based on the overlapping features of PDHc deficiency with those of the disorders of the oxidative phosphorylation we suggest performing a fresh muscle biopsy for detailed biochemical analysis in females with a suspected pyruvate dehydrogenase deficiency, followed by molecular genetic analysis of the PDHA1 gene.
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Affiliation(s)
- Marjolein Willemsen
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 Nijmegen, HB, The Netherlands
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Tulinius M, Darin N, Wiklund LM, Holmberg E, Eriksson JE, Lissens W, De Meirleir L, Holme E. A family with pyruvate dehydrogenase complex deficiency due to a novel C>T substitution at nucleotide position 407 in exon 4 of the X-linked Epsilon1alpha gene. Eur J Pediatr 2005; 164:99-103. [PMID: 15558317 DOI: 10.1007/s00431-004-1570-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2004] [Accepted: 10/04/2004] [Indexed: 10/26/2022]
Abstract
UNLABELLED The pyruvate dehydrogenase complex (PDHc; McKusick 312170), localised in the mitochondrial matrix, is a multienzyme complex which converts pyruvate to acetyl-CoA. A deficiency of PDHc leads to inadequate removal of pyruvate and lactate resulting in lactic acidaemia and insufficient energy production. The major cause of PDHc deficiency is a defect in the E1alpha component. The gene of this component is localised to Xp22.1. We describe two brothers with a relatively mild clinical phenotype of PDHc deficiency. Onset of disease was associated with muscle weakness and swallowing difficulties in both. At follow-up, the older brother developed encephalopathic features consistent with Leigh syndrome. Lactate to pyruvate ratios were low, consistent with a PDHc deficiency which was confirmed by measurements of PDHc activity in thrombocytes. A 407C>T change in exon 4 of the E1alpha gene was found in both brothers and their mother. This substitution predicts a replacement of a conserved alanine at position 136 by valine. CONCLUSION Due to the X-linked inheritance pattern combined with the overall results of clinical investigations, molecular genetic findings and a corresponding functional deficiency of the gene product we believe that this substitution in the pyruvate dehydrogenase E1alpha gene is a mutation leading to pyruvate dehydrogenase complex deficiency in this family.
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Affiliation(s)
- Már Tulinius
- Department of Paediatrics, Sahlgrenska University Hospital/Ostra, 41685 Göteborg, Sweden.
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Abstract
Mitochondrial disorders cause a wide spectrum of diseases in children. Their presentation is nonspecific with encephalomyopathy, failure to thrive, seizures, ophthalmoplegia, and sensorineural hearing loss. These disorders are progressive and are aggravated by fever and infections. They can be caused by mutations in nDNA or mtDNA. Diagnosis requires a complex battery of clinical studies coupled with diagnostic findings on muscle biopsy (abnormal structure, histochemistry, or enzyme studies) or DNA testing. Therapy for mitochondrial disorders remains largely ineffective.
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Affiliation(s)
- Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, 2C412 SOM, 50 North Medical Drive, Salt Lake City, UT 84132, USA.
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Wu YG, Chen WY, Zhang ZW, Yang GZ, Li W, Duggleby RG. Biochemical characterization of two mutants of human pyruvate dehydrogenase, F205L and T231A of the E1alpha subunit. J Inherit Metab Dis 2003; 26:671-4. [PMID: 14707515 DOI: 10.1023/b:boli.0000005628.16515.01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mutations in the E1alpha subunit of the pyruvate dehydrogenase multienzyme complex may result in congenital lactic acidosis, but little is known about the consequences of these mutations at the enzymatic level. Here we characterize two mutants (F205L and T231A) of human pyruvate dehydrogenase in vitro, using the enzyme expressed in Escherichia coli. Wild-type and mutant proteins were purified successfully and their kinetic parameters were measured. F205L shows impaired binding of the thiamin diphosphate cofactor, which may explain why patients carrying this mutation respond to high-dose vitamin B1 therapy. T231A has very low activity and a greatly elevated Km for pyruvate, and this combination of effects would be expected to result in severe lactic acidosis. The results lead to a better understanding of the consequences of these mutations on the functional and structural properties of the enzyme, which may lead to improved therapies for patients carrying these mutations.
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Affiliation(s)
- Yong-Ge Wu
- Life Science College, Jilin University, Changchun, Peoples Republic of China
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