1
|
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] [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.
Collapse
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
| |
Collapse
|
2
|
Kareem O, Nisar S, Tanvir M, Muzaffer U, Bader GN. Thiamine deficiency in pregnancy and lactation: implications and present perspectives. Front Nutr 2023; 10:1080611. [PMID: 37153911 PMCID: PMC10158844 DOI: 10.3389/fnut.2023.1080611] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 04/03/2023] [Indexed: 05/10/2023] Open
Abstract
During pregnancy, many physiologic changes occur in order to accommodate fetal growth. These changes require an increase in many of the nutritional needs to prevent long-term consequences for both mother and the offspring. One of the main vitamins that are needed throughout the pregnancy is thiamine (vitamin B1) which is a water-soluble vitamin that plays an important role in many metabolic and physiologic processes in the human body. Thiamine deficiency during pregnancy can cause can have many cardiac, neurologic, and psychological effects on the mother. It can also dispose the fetus to gastrointestinal, pulmonological, cardiac, and neurologic conditions. This paper reviews the recently published literature about thiamine and its physiologic roles, thiamine deficiency in pregnancy, its prevalence, its impact on infants and subsequent consequences in them. This review also highlights the knowledge gaps within these topics.
Collapse
Affiliation(s)
- Ozaifa Kareem
- Department of Pharmaceutical Sciences, University of Kashmir, Srinagar, India
- *Correspondence: Ozaifa Kareem, ,
| | - Sobia Nisar
- Department of Medicine, Government Medical College, Srinagar, India
| | - Masood Tanvir
- Department of Medicine, Government Medical College, Srinagar, India
| | - Umar Muzaffer
- Department of Medicine, Government Medical College, Srinagar, India
| | - G. N. Bader
- Department of Pharmaceutical Sciences, University of Kashmir, Srinagar, India
- G. N. Bader,
| |
Collapse
|
3
|
Identification of CR43467 encoding a long non-coding RNA as a novel genetic interactant with dFIG4, a CMT-causing gene. Exp Cell Res 2019; 386:111711. [PMID: 31704059 DOI: 10.1016/j.yexcr.2019.111711] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 12/15/2022]
Abstract
The eye imaginal disc-specific knockdown of dFIG4, a Drosophila homolog of FIG4 that is one of the Charcot-Marie-Tooth disease (CMT)-causing genes, induces an aberrant adult compound eye morphology, the so-called rough eye phenotype. We previously performed modifier screening on the dFIG4 knockdown-induced rough eye phenotype and identified several genes, including CR18854, encoding a long non-coding RNA (lncRNA) as genetic interactants with dFIG4. In the present study, in more extensive genetic screening, we found that the deletion of a gene locus encoding both Odorant rector 46a (Or46a) and lncRNA CR43467 effectively suppressed the rough eye phenotype induced by the knockdown of dFIG4. Both genes were located on the same locus, but oriented in opposite directions. In order to identify which of these genes is responsible for the suppression of the rough eye phenotype, we established a CR43467-specific knockdown line using the CRISPR-dCas9 system. By using this system, we demonstrated that the CR43467 gene, but not the Or46a gene, genetically interacted with the dFIG4 gene. The knockdown of CR43467 rescued the reductions in the length of synaptic branches and number of boutons at neuromuscular junctions induced by the knockdown of dFIG4. The vacuole enlargement phenotype induced by the fat body-specific dFIG4 knockdown was also effectively suppressed by the knockdown of CR43467. The knockdown of CR43467 also suppressed the rough eye phenotype induced by other peripheral neuropathy-related genes, such as dCOA7, dHADHB, and dPDHB. We herein identified another gene encoding lncRNA, CR43467 as a genetic interactant with the CMT-causing gene.
Collapse
|
4
|
Li J, Suda K, Ueoka I, Tanaka R, Yoshida H, Okada Y, Okamoto Y, Hiramatsu Y, Takashima H, Yamaguchi M. Neuron-specific knockdown of Drosophila HADHB induces a shortened lifespan, deficient locomotive ability, abnormal motor neuron terminal morphology and learning disability. Exp Cell Res 2019; 379:150-158. [DOI: 10.1016/j.yexcr.2019.03.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/29/2019] [Accepted: 03/30/2019] [Indexed: 01/03/2023]
|
5
|
Dhir S, Tarasenko M, Napoli E, Giulivi C. Neurological, Psychiatric, and Biochemical Aspects of Thiamine Deficiency in Children and Adults. Front Psychiatry 2019; 10:207. [PMID: 31019473 PMCID: PMC6459027 DOI: 10.3389/fpsyt.2019.00207] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/22/2019] [Indexed: 01/19/2023] Open
Abstract
Thiamine (vitamin B1) is an essential nutrient that serves as a cofactor for a number of enzymes, mostly with mitochondrial localization. Some thiamine-dependent enzymes are involved in energy metabolism and biosynthesis of nucleic acids whereas others are part of the antioxidant machinery. The brain is highly vulnerable to thiamine deficiency due to its heavy reliance on mitochondrial ATP production. This is more evident during rapid growth (i.e., perinatal periods and children) in which thiamine deficiency is commonly associated with either malnutrition or genetic defects. Thiamine deficiency contributes to a number of conditions spanning from mild neurological and psychiatric symptoms (confusion, reduced memory, and sleep disturbances) to severe encephalopathy, ataxia, congestive heart failure, muscle atrophy, and even death. This review discusses the current knowledge on thiamine deficiency and associated morbidity of neurological and psychiatric disorders, with special emphasis on the pediatric population, as well as the putative beneficial effect of thiamine supplementation in autism spectrum disorder (ASD) and other neurological conditions.
Collapse
Affiliation(s)
- Shibani Dhir
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Maya Tarasenko
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Davis, CA, United States
| |
Collapse
|
6
|
Dung VM, Suong DNA, Okamaoto Y, Hiramatsu Y, Thao DTP, Yoshida H, Takashima H, Yamaguchi M. Neuron-specific knockdown of Drosophila PDHB induces reduction of lifespan, deficient locomotive ability, abnormal morphology of motor neuron terminals and photoreceptor axon targeting. Exp Cell Res 2018; 366:92-102. [PMID: 29501567 DOI: 10.1016/j.yexcr.2018.02.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/24/2018] [Accepted: 02/27/2018] [Indexed: 02/03/2023]
Abstract
Pyruvate dehydrogenase complex deficiency (PDCD) is a common primary cause of defects in mitochondrial function and also can lead to peripheral neuropathy. Pyruvate dehydrogenase E1 component subunit beta (PDHB) is a subunit of pyruvate dehydrogenase E1, which is a well-known component of PDC. In Drosophila melanogaster, the CG11876 (dPDHB) gene is a homolog of human PDHB. In this study, we established a Drosophila model with neuron-specific knockdown of dPDHB to investigate its role in neuropathy pathogenesis. Knockdown of dPDHB in pan-neurons induced locomotor defects in both larval and adult stages, which were consistent with abnormal morphology of the motor neuron terminals at neuromuscular junctions and mitochondrial fragmentation in brains. Moreover, neuron-specific knockdown of dPDHB also shortened the lifespan of adult flies. In addition, flies with knockdown of dPDHB manifested a rough eye phenotype and aberrant photoreceptor axon targeting. These results with the Drosophila model suggest the involvement of PDHB in peripheral neuropathy.
Collapse
Affiliation(s)
- Vuu My Dung
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; Department of Molecular and Environmental Biotechnology, Faculty of Biology and Biotechnology, University of Science, Vietnam National University - Ho Chi Minh City, Ho Chi Minh City 700000, Vietnam
| | - Dang Ngoc Anh Suong
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Yuji Okamaoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yu Hiramatsu
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Dang Thi Phuong Thao
- Department of Molecular and Environmental Biotechnology, Faculty of Biology and Biotechnology, University of Science, Vietnam National University - Ho Chi Minh City, Ho Chi Minh City 700000, Vietnam
| | - Hideki Yoshida
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Masamitsu Yamaguchi
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
| |
Collapse
|
7
|
Chaturvedi S, Singh AK, Keshari AK, Maity S, Sarkar S, Saha S. Human Metabolic Enzymes Deficiency: A Genetic Mutation Based Approach. SCIENTIFICA 2016; 2016:9828672. [PMID: 27051561 PMCID: PMC4804091 DOI: 10.1155/2016/9828672] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 01/21/2016] [Accepted: 01/31/2016] [Indexed: 05/30/2023]
Abstract
One of the extreme challenges in biology is to ameliorate the understanding of the mechanisms which emphasize metabolic enzyme deficiency (MED) and how these pretend to have influence on human health. However, it has been manifested that MED could be either inherited as inborn error of metabolism (IEM) or acquired, which carries a high risk of interrupted biochemical reactions. Enzyme deficiency results in accumulation of toxic compounds that may disrupt normal organ functions and cause failure in producing crucial biological compounds and other intermediates. The MED related disorders cover widespread clinical presentations and can involve almost any organ system. To sum up the causal factors of almost all the MED-associated disorders, we decided to embark on a less traveled but nonetheless relevant direction, by focusing our attention on associated gene family products, regulation of their expression, genetic mutation, and mutation types. In addition, the review also outlines the clinical presentations as well as diagnostic and therapeutic approaches.
Collapse
Affiliation(s)
- Swati Chaturvedi
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
| | - Ashok K. Singh
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
| | - Amit K. Keshari
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
| | - Siddhartha Maity
- Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India
| | - Srimanta Sarkar
- Dr. Reddy's Laboratories Limited, Bachupally, Hyderabad, Telangana 502325, India
| | - Sudipta Saha
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Vidyavihar, Lucknow 226025, India
| |
Collapse
|
8
|
Thiamine-Responsive and Non-responsive Patients with PDHC-E1 Deficiency: A Retrospective Assessment. JIMD Rep 2014; 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] [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.
Collapse
|
9
|
Agenesis of the Corpus Callosum and Skeletal Deformities in Two Unrelated Patients: Analysis via MRI and Radiography. Case Rep Orthop 2014; 2014:186973. [PMID: 24592343 PMCID: PMC3926397 DOI: 10.1155/2014/186973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 10/30/2013] [Indexed: 11/18/2022] Open
Abstract
Purpose. Mental retardation, mild to severe epilepsy and cerebral palsy often of hemiplegic type are common accompaniments in patients with agenesis/hypoplasia of the corpus callosum. Skeletal deformities of bilateral radiohumeral synostosis, brachydactyly, bilateral elbow dislocation, talipes equinovarus, and juxtacalcaneal accessory bones have been encountered in two unrelated children with agenesis of the corpus callosum. Methods. We report on two unrelated children who presented with the full clinical criteria of agenesis of the corpus callosum. Strikingly, both presented with variable upper and lower limb deformities. The clinical features, radiographic and MRI findings in our current patients, have been compared with previously reported cases identified through a PubMed literature review. Results.
Bilateral radiohumeral synostosis associated with pyruvate dehydrogenase deficiency has been encountered in one patient. The other patient manifested bilateral elbow dislocation, coxa valga, talipes equinovarus, and bilateral juxtacalcaneal accessory bones. Conclusion. The constellation of malformation complexes in our current patients have the hitherto not been reported and expanding the spectrum of skeletal deformities in connection with agenesis of the corpus callosum.
Collapse
|
10
|
Demethylation of the coding region triggers the activation of the human testis-specific PDHA2 gene in somatic tissues. PLoS One 2012; 7:e38076. [PMID: 22675509 PMCID: PMC3365900 DOI: 10.1371/journal.pone.0038076] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 04/30/2012] [Indexed: 11/20/2022] Open
Abstract
Human PDHA2 is a testis-specific gene that codes for the E(1)α subunit of Pyruvate Dehydrogenase Complex (PDC), a crucial enzyme system in cell energy metabolism. Since activation of the PDHA2 gene in somatic cells could be a new therapeutic approach for PDC deficiency, we aimed to identify the regulatory mechanisms underlying the human PDHA2 gene expression. Functional deletion studies revealed that the -122 to -6 promoter region is indispensable for basal expression of this TATA-less promoter, and suggested a role of an epigenetic program in the control of PDHA2 gene expression. Indeed, treatment of SH-SY5Y cells with the hypomethylating agent 5-Aza-2'-deoxycytidine (DAC) promoted the reactivation of the PDHA2 gene, by inducing the recruitment of the RNA polymerase II to the proximal promoter region and the consequent increase in PDHA2 mRNA levels. Bisulfite sequencing analysis revealed that DAC treatment induced a significant demethylation of the CpG island II (nucleotides +197 to +460) in PDHA2 coding region, while the promoter region remained highly methylated. Taken together with our previous results that show an in vivo correlation between PDHA2 expression and the demethylation of the CpG island II in testis germ cells, the present results show that internal methylation of the PDHA2 gene plays a part in its repression in somatic cells. In conclusion, our data support the novel finding that methylation of the PDHA2 coding region can inhibit gene transcription. This represents a key mechanism for absence of PDHA2 expression in somatic cells and a target for PDC therapy.
Collapse
|
11
|
Ojano-Dirain C, Glushakova LG, Zhong L, Zolotukhin S, Muzyczka N, Srivastava A, Stacpoole PW. An animal model of PDH deficiency using AAV8-siRNA vector-mediated knockdown of pyruvate dehydrogenase E1α. Mol Genet Metab 2010; 101:183-91. [PMID: 20685142 PMCID: PMC2950252 DOI: 10.1016/j.ymgme.2010.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 07/08/2010] [Accepted: 07/08/2010] [Indexed: 11/18/2022]
Abstract
We evaluated the feasibility of self-complementary adeno-associated virus (scAAV) vector-mediated knockdown of the pyruvate dehydrogenase complex using small interfering RNAs directed against the E1α subunit gene (PDHA1). AAV serotype 8 was used to stereotaxically deliver scAAV8-si3-PDHA1-Enhanced Green Fluorescent Protein (knockdown) or scAAV8-EGFP (control) vectors into the right striatum and substantia nigra of rats. Rotational asymmetry was employed to quantify abnormal rotation following neurodegeneration in the nigrostriatal system. By 20weeks after surgery, the siRNA-injected rats exhibited higher contralateral rotation during the first 10min following amphetamine administration and lower 90-min total rotations (p≤0.05). Expression of PDC E1α, E1β and E2 subunits in striatum was decreased (p≤0.05) in the siRNA-injected striatum after 14weeks. By week 25, both PDC activity and expression of E1α were lower (p≤0.05) in siRNA-injected striata compared to controls. E1α expression was associated with PDC activity (R(2)=0.48; p=0.006) and modestly associated with counterclockwise rotation (R(2)=0.51;p=0.07). The use of tyrosine-mutant scAAV8 vectors resulted in ~17-fold increase in transduction efficiency of rat striatal neurons in vivo. We conclude that scAAV8-siRNA vector-mediated knockdown of PDC E1α in brain regions typically affected in humans with PDC deficiency results in a reproducible biochemical and clinical phenotype in rats that may be further enhanced with the use of tyrosine-mutant vectors.
Collapse
Affiliation(s)
- Carolyn Ojano-Dirain
- Division of Endocrinology and Metabolism, Department of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Lyudmyla G. Glushakova
- Division of Endocrinology and Metabolism, Department of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Li Zhong
- Powell Gene Therapy Center and Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, 32610, USA
| | - Sergei Zolotukhin
- Powell Gene Therapy Center and Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, 32610, USA
| | - Nicholas Muzyczka
- Powell Gene Therapy Center and Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
| | - Arun Srivastava
- Powell Gene Therapy Center and Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, 32610, USA
| | - Peter W. Stacpoole
- Division of Endocrinology and Metabolism, Department of Medicine, University of Florida, Gainesville, FL, 32610, USA
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32610, USA
- To whom correspondence should be addressed at P.O. Box 100226, University of Florida College of Medicine, Gainesville, FL 32610, USA. Tel: 352-273-9023, Fax: 352-273-9013,
| |
Collapse
|
12
|
Vijayakrishnan S, Kelly S, Gilbert R, Callow P, Bhella D, Forsyth T, Lindsay J, Byron O. Solution structure and characterisation of the human pyruvate dehydrogenase complex core assembly. J Mol Biol 2010; 399:71-93. [PMID: 20361979 PMCID: PMC2880790 DOI: 10.1016/j.jmb.2010.03.043] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 03/19/2010] [Accepted: 03/23/2010] [Indexed: 12/02/2022]
Abstract
Mammalian pyruvate dehydrogenase complex (PDC) is a key multi-enzyme assembly that is responsible for glucose homeostasis maintenance and conversion of pyruvate into acetyl-CoA. It comprises a central pentagonal dodecahedral core consisting of two subunit types (E2 and E3BP) to which peripheral enzymes (E1 and E3) bind tightly but non-covalently. Currently, there are two conflicting models of PDC (E2+E3BP) core organisation: the 'addition' model (60+12) and the 'substitution' model (48+12). Here we present the first ever low-resolution structures of human recombinant full-length PDC core (rE2/E3BP), truncated PDC core (tE2/E3BP) and native bovine heart PDC core (bE2/E3BP) obtained by small-angle X-ray scattering and small-angle neutron scattering. These structures, corroborated by negative-stain and cryo electron microscopy data, clearly reveal open pentagonal core faces, favouring the 'substitution' model of core organisation. The native and recombinant core structures are all similar to the truncated bacterial E2 core crystal structure obtained previously. Cryo-electron microscopy reconstructions of rE2/E3BP and rE2/E3BP:E3 directly confirm that the core has open pentagonal faces, agree with scattering-derived models and show density extending outwards from their surfaces, which is much more structurally ordered in the presence of E3. Additionally, analytical ultracentrifugation characterisation of rE2/E3BP, rE2 (full-length recombinant E2-only) and tE2/E3BP supports the substitution model. Superimposition of the small-angle neutron scattering tE2/E3BP and truncated bacterial E2 crystal structures demonstrates conservation of the overall pentagonal dodecahedral morphology, despite evolutionary diversity. In addition, unfolding studies using circular dichroism and tryptophan fluorescence spectroscopy show that the rE2/E3BP is less stable than its rE2 counterpart, indicative of a role for E3BP in core destabilisation. The architectural complexity and lower stability of the E2/E3BP core may be of benefit to mammals, where sophisticated fine-tuning is required for cores with optimal catalytic and regulatory efficiencies.
Collapse
Key Words
- pdc, pyruvate dehydrogenase complex
- ogdc, 2-oxoglutarate dehydrogenase complex
- ld, lipoyl domain
- sbd, subunit binding domain
- ctd, c-terminal domain
- pdb, protein data bank
- em, electron microscopy
- auc, analytical ultracentrifugation
- saxs, small-angle x-ray scattering
- sans, small-angle neutron scattering
- sv, sedimentation velocity
- se, sedimentation equilibrium
- gfc, gel-filtration chromatography
- hbm, hydrodynamic bead model
- sas, small-angle scattering
- ctf, contrast transfer function
- edta, ethylenediaminetetraacetic acid
- embl, european molecular biology laboratory
- ill, institut laue langevin
- pyruvate dehydrogenase complex
- sas
- auc
- cryo-em
- gdmcl unfolding
Collapse
Affiliation(s)
- S. Vijayakrishnan
- Division of Molecular and Cell Biology, Faculty of Biomedical and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, UK
- Division of Infection and Immunity, Faculty of Biomedical and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow G12 8TA, UK
| | - S.M. Kelly
- Division of Molecular and Cell Biology, Faculty of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - R.J.C. Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - P. Callow
- EPSAM and ISTM Research Institutes, Keele University, Staffordshire ST5 5BG, UK
- Partnership for Structural Biology, Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble, France
| | - D. Bhella
- Institute of Virology, University of Glasgow, Church Street, Glasgow G11 5JR, UK
| | - T. Forsyth
- EPSAM and ISTM Research Institutes, Keele University, Staffordshire ST5 5BG, UK
- Partnership for Structural Biology, Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble, France
| | - J.G. Lindsay
- Division of Molecular and Cell Biology, Faculty of Biomedical and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - O. Byron
- Division of Infection and Immunity, Faculty of Biomedical and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow G12 8TA, UK
| |
Collapse
|
13
|
Barnerias C, Saudubray JM, Touati G, De Lonlay P, Dulac O, Ponsot G, Marsac C, Brivet M, Desguerre I. Pyruvate dehydrogenase complex deficiency: four neurological phenotypes with differing pathogenesis. Dev Med Child Neurol 2010; 52:e1-9. [PMID: 20002125 DOI: 10.1111/j.1469-8749.2009.03541.x] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To describe the phenotype and genotype of pyruvate dehydrogenase complex (PDHc) deficiency. METHOD Twenty-two participants with enzymologically and genetically confirmed PDHc deficiency were analysed for clinical and imaging features over a 15-year period. RESULTS Four groups were identified: (1) those with neonatal encephalopathy with lactic acidosis (one male, four females; diagnosis at birth); (2) those with non-progressive infantile encephalopathy (three males, three females; age at diagnosis 2-9mo); (3) those with Leigh syndrome (eight males; age at diagnosis 1-13mo); and (4) those with relapsing ataxia (three males; 18-30mo). Seventeen mutations involved PDHA1 (a hotspot was identified in exons 6, 7, and 8 in seven males with Leigh syndrome or recurrent ataxia). Mutations in the PDHX gene (five cases) were correlated with non-progressive encephalopathy and long-term survival in four cases. INTERPRETATION Two types of neurological involvement were identified. Abnormal prenatal brain development resulted in severe non-progressive encephalopathy with callosal agenesis, gyration anomalies, microcephaly with intrauterine growth retardation, or dysmorphia in both males and females (12 cases). Acute energy failure in infant life produced basal ganglia lesions with paroxysmal dystonia, neuropathic ataxia due to axonal transport dysfunction, or epilepsy only in males (11 cases). The ketogenic diet improved only paroxysmal dysfunction, providing an additional argument in favour of paroxysmal energy failure.
Collapse
|
14
|
Pliss L, Pentney RJ, Johnson MT, Patel MS. Biochemical and structural brain alterations in female mice with cerebral pyruvate dehydrogenase deficiency. J Neurochem 2005; 91:1082-91. [PMID: 15569252 DOI: 10.1111/j.1471-4159.2004.02790.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyruvate dehydrogenase complex (PDC) deficiency is an inborn metabolic disorder associated with a variety of neurologic abnormalities. This report describes the development and initial characterization of a novel murine model system in which PDC deficiency has been introduced specifically into the developing nervous system. The absence of liveborn male and a roughly 50% reduction in female offspring following induction of the X-linked mutation indicate that extensive deficiency of PDC in the nervous system leads to pre-natal lethality. Brain tissue from surviving females at post-natal days 15 and 35 was shown to have approximately 75% of wild-type PDC activity, suggesting that a threshold of enzyme activity exists for post-natal survival. Detailed histological analyses of brain tissue revealed structural defects such as disordered neuronal cytoarchitecture and neuropil fibers in grey matter, and reduced size of bundles and disorganization of fibers in white matter. Many of the histologic abnormalities resemble those found in human female patients who carry mutations in the X-linked ortholog. These findings demonstrate a requirement for PDC activity within the nervous system for survival in utero and suggest that impaired pyruvate metabolism in the developing brain can affect neuronal migration, axonal growth and cell-cell interactions.
Collapse
Affiliation(s)
- Lioudmila Pliss
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | | | | | | |
Collapse
|
15
|
Schwab MA, Kölker S, van den Heuvel LP, Sauer S, Wolf NI, Rating D, Hoffmann GF, Smeitink JAM, Okun JG. Optimized spectrophotometric assay for the completely activated pyruvate dehydrogenase complex in fibroblasts. Clin Chem 2004; 51:151-60. [PMID: 15550478 DOI: 10.1373/clinchem.2004.033852] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Analysis of the pyruvate dehydrogenase complex (PDHc) activity in human skin fibroblasts is hampered by low enzyme activity in the cells. The most commonly used radiochemical method detects the formation of (14)CO(2), an endproduct of the E1 component of PDHc, from [1-(14)C]pyruvate. METHODS We report a spectrophotometric method for the analysis of PDHc activity in fibroblasts based on detection of NADH formation via a p-iodonitrotetrazolium violet (INT)-coupled system. We investigated in detail the specific requirements of this assay, such as cofactor requirements and the effects of suggested stimulatory compounds and different cell disruption procedures. The reliability of the optimized assay was studied by investigation of patients previously diagnosed with PDHc deficiency and by comparison with results from the radiochemical method. RESULTS Mean (SD) total PDHc activities were 136 (31) and 58 (21) mU/U of citrate synthase in fibroblast homogenates from 10 healthy volunteers and 7 PDHc-deficient patients, respectively, by the spectrophotometric assay. Similar results were obtained in a mitochondrial fraction. Dithiothreitol (DTT) increased the nonspecific inhibitor-insensitive rate with less pronounced effect on the specific rate of PDHc activity. Administration of DTT increased PDHc activity to 193 (3)% of control activity (without DTT), but decreased the inhibitor-sensitive rate from 99 (0.3)% (without DTT) to 69 (2)% (with 0.3 mmol/L DTT). CONCLUSION The simple, optimized spectrophotometric assay for PDHc analysis allows reliable investigation of the enzyme complex in human skin fibroblasts.
Collapse
Affiliation(s)
- Marina A Schwab
- Division of Metabolic and Endocrine Diseases, University Children's Hospital Heidelberg, 69120 Heidelberg, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
A two-year-old, intact female Sussex spaniel was presented with signs of exercise intolerance. Pre- and post-exercise serum lactate and pyruvate concentrations and urinary organic acid screening supported a diagnosis of pyruvate dehydrogenase deficiency, as previously reported in this breed. Dietary therapy was initiated for six months, during which time there was no reported clinical deterioration. A full neurological examination and repeat evaluation of lactate and pyruvate concentrations before and after exercise was conducted one year after diagnosis, at which time the patient had been without dietary modification for six months and had developed more severe exercise intolerance along with evidence of central nervous system dysfunction.
Collapse
Affiliation(s)
- C J Abramson
- Centre for Small Animal Studies, Animal Health Trust, Suffolk CB8 7UU
| | | | | |
Collapse
|
17
|
Dey R, Aral B, Abitbol M, Marsac C. Pyruvate dehydrogenase deficiency as a result of splice-site mutations in the PDX1 gene. Mol Genet Metab 2002; 76:344-7. [PMID: 12208141 DOI: 10.1016/s1096-7192(02)00104-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mutations in the E3-binding protein component of pyruvate dehydrogenase complex have been demonstrated in a few cases of Leigh syndrome. We report that two mutations previously detected in the E3-binding protein cDNA are the consequence of splice-site mutations. Both involved a single base substitution in the conserved dinucleotides of splice junctions, one leading to skipping of an exon and the other, to activation of a cryptic site. Our findings add to the understanding of molecular basis of E3-binding protein deficiency and indicate yet again the high frequency of splicing mutations in this gene.
Collapse
Affiliation(s)
- Runu Dey
- Laboratoire CERTO, Faculté de Medécine Necker, 156 rue de Vaugirard, Paris, France
| | | | | | | |
Collapse
|
18
|
Lib MY, Brown RM, Brown GK, Marusich MF, Capaldi RA. Detection of pyruvate dehydrogenase E1 alpha-subunit deficiencies in females by immunohistochemical demonstration of mosaicism in cultured fibroblasts. J Histochem Cytochem 2002; 50:877-84. [PMID: 12070266 DOI: 10.1177/002215540205000701] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Deficiency of the E1 alpha-subunit of the pyruvate dehydrogenase (PDH) complex is an X-linked inborn error of metabolism and one of the major causes of lactic acidosis in children. Although most heterozygous females manifest symptoms of the disease, it is often difficult to establish the diagnosis as results based on measurement of total PDH activity, and E1 alpha-immunoreactive protein in patient fibroblasts may be ambiguous because of the variability in the pattern of X chromosome inactivation. We report the development of a set of monoclonal antibodies (MAbs) specific to four subunits of the PDH complex that can be used for detection of PDH E1 alpha deficiency. We also show that anti-E1 alpha and anti-E2 MAbs, when used in immunocytochemical analysis, can detect mosaicism in cell cultures from female patients in which as few as 2-5% of cells express the deficiency. This immunocytochemical approach, which is fast, reliable, and quantitative, will be particularly useful in identifying females with PDH E1 alpha-subunit deficiency as a precursor to mutation analysis.
Collapse
|
19
|
Roche TE, Baker JC, Yan X, Hiromasa Y, Gong X, Peng T, Dong J, Turkan A, Kasten SA. Distinct regulatory properties of pyruvate dehydrogenase kinase and phosphatase isoforms. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2002; 70:33-75. [PMID: 11642366 DOI: 10.1016/s0079-6603(01)70013-x] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mammalian pyruvate dehydrogenase complex (PDC) plays central and strategic roles in the control of the use of glucose-linked substrates as sources of oxidative energy or as precursors in the biosynthesis of fatty acids. The activity of this mitochondrial complex is regulated by the continuous operation of competing pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase phosphatase (PDP) reactions. The resulting interconversion cycle determines the fraction of active (nonphosphorylated) pyruvate dehydrogenase (E1) component. Tissue-specific and metabolic state-specific control is achieved by the selective expression and distinct regulatory properties of at least four PDK isozymes and two PDP isozymes. The PDK isoforms are members of a family of serine kinases that are not structurally related to cytoplasmic Ser/Thr/Tyr kinases. The catalytic subunits of the PDP isoforms are Mg2+-dependent members of the phosphatase 2C family that has binuclear metal-binding sites within the active site. The dihydrolipoyl acetyltransferase (E2) and the dihydrolipoyl dehydrogenase-binding protein (E3BP) are multidomain proteins that form the oligomeric core of the complex. One or more of their three lipoyl domains (two in E2) selectively bind each PDK and PDP1. These adaptive interactions predominantly influence the catalytic efficiencies and effector control of these regulatory enzymes. When fatty acids are the preferred source of acetyl-CoA and NADH, feedback inactivation of PDC is accomplished by the activity of certain kinase isoforms being stimulated upon preferentially binding a lipoyl domain containing a reductively acetylated lipoyl group. PDC activity is increased in Ca2+-sensitive tissues by elevating PDP1 activity via the Ca2+-dependent binding of PDP1 to a lipoyl domain of E2. During starvation, the irrecoverable loss of glucose carbons is restricted by minimizing PDC activity due to high kinase activity that results from the overexpression of specific kinase isoforms. Overexpression of the same PDK isoforms deleteriously hinders glucose consumption in unregulated diabetes.
Collapse
Affiliation(s)
- T E Roche
- Department of Biochemistry, Kansas State University, Manhattan 66506-3702, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Dahl HH, Thorburn DR. Mitochondrial diseases: beyond the magic circle. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 106:1-3. [PMID: 11579419 DOI: 10.1002/ajmg.1427] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- H H Dahl
- Gene Identification and Expression Laboratory, Murdoch Childrens Research institute, Parkville, Victoria, Australia.
| | | |
Collapse
|
21
|
Abstract
Mitochondrial diseases are a heterogeneous group of disorders with widely varying clinical features, due to defects in mitochondrial function. Involvement of both muscle and nerve is common in mitochondrial disease. In some cases, this involvement is subclinical or a minor part of a multisystem disorder, but myopathy and neuropathy are a major, often presenting, feature of a number of mitochondrial syndromes. In addition, mitochondrial dysfunction may play a role in a number of classic neuromuscular diseases. This article reviews the role of mitochondrial dysfunction in neuromuscular disease and discusses a rational approach to diagnosis and treatment of patients presenting with a neuromuscular syndrome due to mitochondrial disease.
Collapse
Affiliation(s)
- R A Nardin
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Harvard Institute of Medicine, Rm 858, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
22
|
Rouillac C, Aral B, Fouque F, Marchant D, Saudubray JM, Dumez Y, Lindsay G, Abitbol M, Dufier JL, Marsac C, Benelli C. First prenatal diagnosis of defects in the HsPDX1 gene encoding protein X, an additional lipoyl-containing subunit of the human pyruvate dehydrogenase complex. Prenat Diagn 1999; 19:1160-4. [PMID: 10590436 DOI: 10.1002/(sici)1097-0223(199912)19:12<1160::aid-pd712>3.0.co;2-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have previously reported a genetic study of a neonatal lactic acidosis linked to a pyruvate dehydrogenase complex deficiency due to the absence of the protein X subunit. This rare autosomal recessive disorder is associated with specific deletions in this polypeptide which is encoded by the HsPDX1 gene, located on chromosome 11p1.3. The pathology of the patient was considered to arise from a large homozygous deletion (78del85) found at the 5' end of the HsPDX1 coding sequence. Her heterozygous mother underwent prenatal diagnosis during a subsequent pregnancy. Chorionic villus samples were used for three independent studies: (1) normal levels of the protein X component of the PDH complex were detected by immunoblotting; (2) RT-PCR analysis showed no deletion at the 5' end of the cDNA but the presence of a distinct heterozygous deletion (965del59) at its 3' end inherited from the father; (3) haplotype analysis revealed the presence of the father's mutated allele and the mother's normal allele. It was concluded that the fetus was heterozygous for this separate 3' deletion, so, it was likely to be not affected. This study permitted us to characterize more precisely the genetic abnormalities of the HsPDX1 cDNA occurring in each family's member.
Collapse
Affiliation(s)
- C Rouillac
- Centre de Recherches Thérapeutiques en Ophtalmologie (CERTO), Faculté de Médecine Necker, Paris, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Renouil M, Fourmaintraux A, Cartault F, Rodriguez D, Razafinarivo-Schoreitz S, Chaurand G, Wendling C, Bangui A, Ponsot G. [Severe anorexia in infants in Reunion: a new autosomal recessive disease?]. Arch Pediatr 1999; 6:725-34. [PMID: 10429812 DOI: 10.1016/s0929-693x(99)80354-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Infantile anorexia is usually considered as a psychogenic disorder with benign prognosis. However, unusually severe characteristics of infantile anorexia, seen in the south of the island, seem to us in favor of a new metabolic etiology. POPULATION AND METHODS Among 38 known cases, we retrospectively studied the best documented observations of 24 children admitted over the last 25 years to our institution. RESULTS The sex ratio was ten females and 14 males. Twenty-three of the 24 infants lived in formerly isolated localities of the island where other hereditary diseases have been observed with an unusually high frequency. The family pedigrees favoured an autosomal recessive heredity. Severe anorexia, accompanied by irrepressible vomiting (91%), appeared at the age of 8.5 months +/- 3.5. Parenteral (54.2%) or enteral (54.2%) feeding was necessary but did not always avoid death, which occurred in 45.8% of the cases at the age of 24 months +/- 3.5. All of the children which survived had neurological disorders (pyramidal syndrome, ataxia, laryngeal palsy, mental retardation, seizures) which occurred sometimes at an early stage. The investigations did not allow the identification of any known cause. DISCUSSION The elevated level of lactic acid in the cerebral spinal fluid seemed to indicate a possible mitochondrial disorder, eventually a mutation of an autosomal gene of the pyruvate dehydrogenase complex because of the normal lactate/pyruvate ratio, but enzymatic activities were normal. The cerebral MRI showed features of leukodystrophy. On the other hand, the elevated level of plasma serotonin seemed to indicate a disorder of the serotonin metabolism, for which an animal model exists. CONCLUSION We propose to name this new syndrome by the acronym 'RAVINE' which associates Reunion, Anorexia, Vomiting which is Irrepressible, and Neurological signs. Linkage study might allow the localization and isolation of a gene and allow one to start understanding the biological mechanism which we suspect to be an hereditary neurobiological eating disorder.
Collapse
Affiliation(s)
- M Renouil
- Service de pédiatrie, centre hospitalier Sud Réunion, Saint-Pierre, France
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Abstract
Because of the high energy requirements of the growing neonate, disorders of mitochondrial metabolism caused by defects in fatty acid oxidation, pyruvate metabolism, and the respiratory chain may often present in the neonatal period. Common neonatal presentations are hypotonia, lethargy, feeding and respiratory difficulties, failure to thrive, psychomotor delay, seizures, and vomiting. Laboratory clues include alterations in the levels of lactate, pyruvate (and the lactate/pyruvate ratio), glucose, and ketone bodies. Diagnosis usually depends on specific enzyme assays or on molecular genetic analysis. Without treatment, most infants die in the first few days or months of life. In the last decade, there have been significant advances in the understanding of the molecular basis of these disorders. This review discusses the major subgroups of mitochondrial disorders, focusing on defects of pyruvate oxidation, the Krebs cycle, and the respiratory chain. Disorders caused by respiratory chain defects may involve nuclear DNA, mitochondrial DNA, or intergenomic signaling. Recognition and early diagnosis of these conditions are important in the genetic counseling of these families.
Collapse
Affiliation(s)
- C M Sue
- Department of Neurology, H. Houston Merritt Clinical Research Center for Muscular Dystrophy and Related Diseases, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | | | | | | |
Collapse
|
25
|
|
26
|
Wilichowski E, Korenke GC, Ruitenbeek W, De Meirleir L, Hagendorff A, Janssen AJ, Lissens W, Hanefeld F. Pyruvate dehydrogenase complex deficiency and altered respiratory chain function in a patient with Kearns-Sayre/MELAS overlap syndrome and A3243G mtDNA mutation. J Neurol Sci 1998; 157:206-13. [PMID: 9619647 DOI: 10.1016/s0022-510x(98)00068-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Combined alteration of the pyruvate dehydrogenase complex and respiratory chain function is described in a 21 year-old male patient with overlapping MELAS (mitochondrial encephalomyopathy, lactic acidosis, and 'stroke-like' episodes) and Kearns-Sayre syndrome. Progressive external ophthalmoplegia, pigmentary retinopathy and right bundle branch block were present when he experienced the first 'stroke-like' episode at 18 years old. The A>G tRNALeu(UUR) point mutation at nucleotide 3243 of the mitochondrial DNA was predominant in muscle tissue (79%) and present, but at lower levels in fibroblasts (49%) and blood cells (37%). Biochemical analysis revealed diminished activities of pyruvate dehydrogenase (23%) and respiratory chain complexes I and IV (57%, respectively) in muscle, but normal activities in the fibroblasts. Immunochemical studies of the muscular pyruvate dehydrogenase components showed normal content of E1alpha, E1beta and E2 protein. Molecular screening of the E1alpha gene did not indicate a nuclear mutation. These observations suggest that mitochondrial DNA defects may be associated with altered nuclear encoded enzymes which are actively imported into mitochondria and constitute components of the mitochondrial matrix. Biochemical workup of mitochondrial disorders should not be restricted to the respiratory chain even if mitochondrial DNA mutations are present.
Collapse
Affiliation(s)
- E Wilichowski
- Department of Pediatrics and Neuropediatrics, University of Göttingen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Kinoshita H, Sakuragawa N, Tada H, Naito E, Kuroda Y, Nonaka I. Recurrent muscle weakness and ataxia in thiamine-responsive pyruvate dehydrogenase complex deficiency. J Child Neurol 1997; 12:141-4. [PMID: 9075024 DOI: 10.1177/088307389701200212] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- H Kinoshita
- Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | | | | | | | | | | |
Collapse
|
28
|
Fujii T, Garcia Alvarez MB, Sheu KF, Kranz-Eble PJ, De Vivo DC. Pyruvate dehydrogenase deficiency: the relation of the E1 alpha mutation to the E1 beta subunit deficiency. Pediatr Neurol 1996; 14:328-34. [PMID: 8962591 DOI: 10.1016/0887-8994(96)00058-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report 7 patients with pyruvate dehydrogenase (PDH) deficiency caused by mutations of the PDH-E1 alpha subunit. Each patient had a different mutation; 4 with duplicate insertions, 1 with a deletion of tandem repeat, and 2 with point mutations. Five of the mutations were novel, thus confirming allelic heterogeneity. Immunoblot analysis revealed decreased immunoreactivity for the E1 alpha and E1 beta subunits in every patient. Pulse-labeling and chase study for the E1 alpha and E1 beta subunits revealed that initial synthesis of the mutant E1 alpha subunit was normal and posttranslational degradation was complete by 48 hours. However, the post-translational degradation rate of the E1 beta subunit varied from one patient to another. Factors other than instability of the E1 beta monomer must contribute to the degradation rate of this subunit in the presence of an E1 alpha subunit mutation. Including this series, 3 patients with the S312 deletion and 5 with the R302C point mutation have been reported, and all of these patients are female. These findings suggest that these two loci are hot spots for gene mutations, and may be lethal in the male fetus.
Collapse
Affiliation(s)
- T Fujii
- Department of Neurology, College of Physicians and Surgeons of Columbia University, New York, USA
| | | | | | | | | |
Collapse
|
29
|
Otero LJ, Brown GK, Silver K, Arnold DL, Matthews PM. Association of cerebral dysgenesis and lactic acidemia with X-linked PDH E1 alpha subunit mutations in females. Pediatr Neurol 1995; 13:327-32. [PMID: 8771169 DOI: 10.1016/0887-8994(95)00222-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We describe an infant girl who presented at age 4 1/2 months with developmental delay, infantile spasms, hypotonia, and elevated lactate levels in the blood and cerebrospinal fluid. She had minor dysmorphic features. Muscle phosphorus magnetic resonance spectroscopy demonstrated reduced phosphocreatine and increased inorganic phosphate, suggesting a defect in oxidative energy metabolism. Pyruvate dehydrogenase activity in cultured fibroblasts was reduced (0.35 nmol/mg mitochondrial protein/min; controls 0.7-1.1 nmol/mg mitochondrial protein/min). Immunoblotting demonstrated a reduced amount of pyruvate dehydrogenase (PDH) E1 alpha immunoreactive protein with normal amounts of E2 protein. Single-strand conformational polymorphism analysis of E1 alpha cDNA prepared from fibroblasts disclosed an abnormal migration pattern, suggesting heterozygosity for a mutant allele. Dideoxy-fingerprinting of PCR-amplified genomic DNA was used to localize the mutation to exon 10. Direct sequencing demonstrated a novel 13-bp insertion mutation that would lead to premature termination of the protein product. This study further extends the allelic heterogeneity underlying PDH deficiency. The demonstration of bioenergetic abnormalities in muscle emphasizes that hypotonia in PDH deficiency may have combined peripheral and central etiologies. The results further suggest that the association of cerebral dysgenesis with lactic acidemia in females may be a useful clue to PDH deficiency.
Collapse
Affiliation(s)
- L J Otero
- Department of Biochemistry, University of Oxford, UK
| | | | | | | | | |
Collapse
|
30
|
Takakubo F, Thorburn DR, Brown RM, Brown GK, Dahl HH. A novel mutation (P316L) in a female with pyruvate dehydrogenase E1 alpha deficiency. Hum Mutat 1995; 6:274-5. [PMID: 8535453 DOI: 10.1002/humu.1380060317] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- F Takakubo
- Murdoch Institute for Research Into Birth Defects, Royal Children's Hospital, Parkville, Melbourne, Victoria 3052, Australia
| | | | | | | | | |
Collapse
|
31
|
Affiliation(s)
- G K Brown
- Department of Biochemistry, University of Oxford, UK
| | | | | | | |
Collapse
|
32
|
Shevell MI, Matthews PM, Scriver CR, Brown RM, Otero LJ, Legris M, Brown GK, Arnold DL. Cerebral dysgenesis and lactic acidemia: an MRI/MRS phenotype associated with pyruvate dehydrogenase deficiency. Pediatr Neurol 1994; 11:224-9. [PMID: 7880337 DOI: 10.1016/0887-8994(94)90107-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Pyruvate dehydrogenase complex (PDHC) is an intramitochondrial multienzyme complex essential for the aerobic oxidation of glucose. The majority of patients with PDHC deficiency have abnormalities in the major catalytic and regulatory subunit, E1 alpha, which is encoded on the X chromosome. The clinical spectrum of PDHC deficiency is heterogeneous, particularly in heterozygous females, and diagnosis may be difficult. Three affected infant girls with PDHC deficiency were investigated. All had dysmorphic features, microcephaly with profound global developmental delay, and hypotonia. Systemic acidosis was absent, although serum lactate and pyruvate were abnormally elevated. Magnetic resonance imaging revealed hypoplasia of the corpus callosum in all patients. Proton magnetic resonance spectroscopy of brain revealed large increases in relative signal intensities for lactic acid and decreases in the relative signal intensities of N-acetylaspartate, a marker of neuronal damage or less. Phosphorus MRS of muscle revealed abnormally low phosphorylation potentials for all these patients, although the degree of abnormality was variable and not directly correlated with the amount of brain lactate. It is proposed that cerebral dysgenesis and cerebral lactic acidemia as shown by magnetic resonance imaging and proton magnetic resonance spectroscopy are useful diagnostic clues to PDHC deficiency, particularly in females in whom variable patterns of X-inactivation reduce sensitivity of laboratory diagnosis based on the biochemical studies of peripheral tissues. In addition, muscle bioenergetic abnormalities in conjunction with CNS dysfunction may contribute to profound hypotonia in this disorder.
Collapse
Affiliation(s)
- M I Shevell
- Department of Neurology/Neurosurgery, McGill University, Quebec, Canada
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Iannello RC, Young JC, Kola I. Pdha-2: a model for studying transcriptional regulation in early spermatocytes. Mol Reprod Dev 1994; 39:194-9. [PMID: 7826622 DOI: 10.1002/mrd.1080390212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Precise temporal and tissue-specific expression of genes during spermatocyte differentiation is crucial for the formation of functional spermatozoa. However, the mechanisms that regulate gene expression during spermatogenesis are poorly understood. One testis-specific gene, Pdha-2, is beginning to emerge as a potentially important model for the study of these events. This review focuses on our current understanding of the expression and regulation of Pdha-2 during spermatogenesis.
Collapse
Affiliation(s)
- R C Iannello
- Molecular Embryology and Birth Defects Laboratory, Monash Medical Centre, Clayton, Victoria, Australia
| | | | | |
Collapse
|
34
|
Cross JH, Connelly A, Gadian DG, Kendall BE, Brown GK, Brown RM, Leonard JV. Clinical diversity of pyruvate dehydrogenase deficiency. Pediatr Neurol 1994; 10:276-83. [PMID: 8068153 DOI: 10.1016/0887-8994(94)90122-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Clinical features, magnetic resonance, and biochemical studies are reported in 7 children with pyruvate dehydrogenase (PDH) deficiency. These findings confirm the diverse clinical presentation of this condition, although neurological abnormalities are consistent features. Imaging results are also varied. Six of the children were investigated with proton magnetic resonance spectroscopy and lactate was demonstrated in brain in all patients. Regional variation in the lactate signal was observed in those patients in whom 2 regions were examined. Advances in molecular genetics have provided some explanations for the clinical variation in pyruvate dehydrogenase deficiency.
Collapse
Affiliation(s)
- J H Cross
- Neurosciences Unit, Institute of Child Health, London, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
35
|
Abstract
Pyruvate dehydrogenase (PDH) E1 alpha subunit deficiency is an X-linked inborn error of metabolism affecting males and females with equal frequency. The diagnosis is usually based on determination of enzyme activity, although this may present difficulties in some females because of X-inactivation patterns favouring expression of the normal X chromosome. This is a particular problem for prenatal diagnosis using chorionic villus cells where normal enzyme assay results do not necessarily exclude the diagnosis and confirmatory X-inactivation analysis may be complicated by variable methylation of active and inactive X chromosomes. We describe prenatal diagnosis in two pregnancies in a family following diagnosis of a PDH E1 alpha deficient male. The first prenatal diagnosis was performed by enzyme assay, but by the time of the subsequent pregnancy, the underlying mutation in the affected male had been identified and direct gene analysis was possible. This study highlights the limitations of diagnosis of PDH E1 alpha deficiency based on measurement of the gene product and illustrates the need for mutation analysis in affected individuals.
Collapse
Affiliation(s)
- R M Brown
- Department of Biochemistry, University of Oxford, U.K
| | | |
Collapse
|
36
|
Chabrol B, Mancini J, Benelli C, Gire C, Munnich A. Leigh syndrome: pyruvate dehydrogenase defect. A case with peripheral neuropathy. J Child Neurol 1994; 9:52-5. [PMID: 8151084 DOI: 10.1177/088307389400900113] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Pyruvate dehydrogenase deficiency is one of the most common causes of encephalopathy associated with lactic acidosis and is known to account for congenital lactic acidosis, recurrent ataxia, and infantile Leigh syndrome. Hitherto, however, peripheral neuropathy has not been regarded as a presenting symptom of pyruvate dehydrogenase deficiency. Here, we report on a boy who presented peripheral neuropathy with severe limb hypotonia, absent deep-tendon reflexes, and reduced motor nerve conduction velocities at 8 months of age. Persistent hyperpyruvicemia with normal lactate/pyruvate molar ratios in plasma were highly suggestive of a pyruvate dehydrogenase deficiency, and the determination of pyruvate dehydrogenase activity in circulating lymphocytes led to the diagnosis of pyruvate decarboxylase (PDH-E1) deficiency in the proband. Based on this observation, we suggest that pyruvate dehydrogenase deficiency should be considered in the diagnosis of peripheral neuropathy in infancy, especially when associated with persistent hyperpyruvicemia, normal lactate/pyruvate molar ratios in plasma, and recurrent episodes of drowsiness and hypotonia of unknown origin.
Collapse
Affiliation(s)
- B Chabrol
- Department of Neuropediatrics, Hôpital d'Enfants, CHU Timone, Marseille, France
| | | | | | | | | |
Collapse
|
37
|
Dahl HH, Brown GK. Pyruvate dehydrogenase deficiency in a male caused by a point mutation (F205L) in the E1 alpha subunit. Hum Mutat 1994; 3:152-5. [PMID: 8199595 DOI: 10.1002/humu.1380030210] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- H H Dahl
- Murdoch Institute for Research into Birth Defects, Royal Children's Hospital, Parkville, Melbourne, Victoria, Australia
| | | |
Collapse
|
38
|
Affiliation(s)
- B H Robinson
- Department of Biochemistry, University of Toronto, Ontario, Canada
| |
Collapse
|
39
|
Michotte A, De Meirleir L, Lissens W, Denis R, Wayenberg JL, Liebaers I, Brucher JM. Neuropathological findings of a patient with pyruvate dehydrogenase E1 alpha deficiency presenting as a cerebral lactic acidosis. Acta Neuropathol 1993; 85:674-8. [PMID: 8337946 DOI: 10.1007/bf00334680] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Neuropathological findings are reported of a 6-month-old female child with a "cerebral" lactic acidosis. A mutation in the pyruvate dehydrogenase (PDH) E1 alpha gene was found. Gross examination of the brain revealed a severe thinning of the cerebral parenchym, a marked hydrocephalus sparing the aqueduct and fourth ventricle, agenesis of the corpus callosum and heterotopic noduli of gray matter in subependymal regions. Microscopical examination showed heterotopic inferior olives, absent pyramids and focal neuroglial overgrowth into meninges. In addition some heterotopia of Purkinje cells and dysplasia of the dentate nuclei were observed. There was a marked vascular proliferation with many thin-walled, congestive vessels in the cerebral and cerebellar white matter, and to a lesser extent in the striatum. To our knowledge these cerebellar and vascular abnormalities have not been reported before in patients with "cerebral" lactic acidosis. The combination of these neuropathological findings might be characteristic for PDH deficiency and more specifically for its E1 alpha subtype. Neuropathological examination could lead to the retrospective diagnosis of PDH E1 alpha deficiency in those cases where biochemical investigations were not or incompletely performed. This may have potential implications for genetic counseling.
Collapse
Affiliation(s)
- A Michotte
- Department of Neurology, AZ-VUB Laarbeeklaan, Brussels, Belgium
| | | | | | | | | | | | | |
Collapse
|
40
|
De Meirleir L, Lissens W, Denis R, Wayenberg JL, Michotte A, Brucher JM, Vamos E, Gerlo E, Liebaers I. Pyruvate dehydrogenase deficiency: clinical and biochemical diagnosis. Pediatr Neurol 1993; 9:216-20. [PMID: 8352855 DOI: 10.1016/0887-8994(93)90088-t] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A female neonate with pyruvate dehydrogenase (PDH) deficiency is presented with clinical, radiologic, biochemical, neuropathologic, and molecular genetic data. She was dysmorphic, with a high forehead, lowset ears, thin upper lip, upturned nose, and rhizomelic limbs. Cranial MRI revealed severe cortical atrophy, ventricular dilatation, and corpus callosum agenesis. Pyruvate and lactate levels were increased in CSF and blood. Urinary organic acid profile was compatible with PDH deficiency. PDH activity was normal in fibroblasts, lymphocytes, and muscle. The PDH E1-alpha gene was sequenced and a single base mutation was found within the regulatory phosphorylation site in exon 10. It is postulated that this mutation causes a cerebral form of PDH deficiency. Tissue-specific expression of the disease could be explained by differential X chromosome inactivation because the PDH E1-alpha gene is located on this chromosome. Dysmorphism with severe cerebral malformations in female patients merits a metabolic evaluation, including determination of lactate and pyruvate levels in CSF.
Collapse
Affiliation(s)
- L De Meirleir
- Department of Pediatrics, Academic Hospital, Free University Brussels, Belgium
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Brown RM, Brown GK. X chromosome inactivation and the diagnosis of X linked disease in females. J Med Genet 1993; 30:177-84. [PMID: 8097254 PMCID: PMC1016294 DOI: 10.1136/jmg.30.3.177] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In studies of female patients with suspected deficiency of the E1 alpha subunit of the pyruvate dehydrogenase complex, we have found that X inactivation ratios of 80:20 or greater occur at sufficient frequency in cultured fibroblasts to make exclusion of the diagnosis impossible in about 25% of cases. Pyruvate dehydrogenase E1 alpha subunit deficiency is an X linked inborn error of metabolism which is well defined biochemically and is unusual in that most heterozygous females manifest the condition. The diagnosis is usually established by measurement of enzyme activity and the level of immunoreactive protein and these analyses are most commonly performed on cultured fibroblasts from the patients. Skewed patterns of X chromosome inactivation make it impossible to exclude the diagnosis if the normal X chromosome is expressed in the majority of cells. While most of the observed variation appears to be the expected consequence of random X inactivation, it may be further exaggerated by sampling and subsequent expansion of the cells for analysis.
Collapse
Affiliation(s)
- R M Brown
- Department of Biochemistry, University of Oxford
| | | |
Collapse
|
42
|
Abstract
The mitochondrion is the only extranuclear organelle containing DNA (mtDNA). As such, genetically determined mitochondrial diseases may result from a molecular defect involving the mitochondrial or the nuclear genome. The first is characterized by maternal inheritance and the second by Mendelian inheritance. Ragged-red fibers (RRF) are commonly seen with primary lesions of mtDNA, but this association is not invariant. Conversely, RRF are seldom associated with primary lesions of nuclear DNA. Large-scale rearrangements (deletions and insertions) and point mutations of mtDNA are commonly associated with RRF and lactic acidosis, e.g. Kearns-Sayre syndrome (KSS) (major large-scale rearrangements), Pearson syndrome (large-scale rearrangements), myoclonus epilepsy with RRF (MERRF) (point mutation affecting tRNA(lys) gene), mitochondrial myopathy, lactic acidosis, and stroke-like episodes (MELAS) (two point mutations affecting tRNA(leu)(UUR) gene) and a maternally-inherited myopathy with cardiac involvement (MIMyCa) (point mutation affecting tRNA(leu)(UUR) gene). However, RRF and lactic acidosis are absent in Leber hereditary optic neuropathy (LHON) (one point mutation affecting ND4 gene, two point mutations affecting ND1 gene, and one point mutation affecting the apocytochrome b subunit of complex III), and the condition associated with maternally inherited sensory neuropathy (N), ataxia (A), retinitis pigmentosa (RP), developmental delay, dementia, seizures, and limb weakness (NARP) (point mutation affecting ATPase subunit 6 gene). The point mutations in MELAS, MIMyCa, and MERRF, and the large-scale mtDNA rearrangements in KSS and Pearson syndrome have a broader biochemical impact since these molecular defects involve the translational sequence of mitochondrial protein synthesis. The nuclear defects involving mitochondrial function generally are not associated with RRF. The biochemical classification of mitochondrial diseases principally catalogues these nuclear defects. This classification divides mitochondrial diseases into five categories. Primary and secondary deficiencies of carnitine are examples of a substrate transport defect. A lipid storage myopathy is often present. Disturbances of pyruvate or fatty acid metabolism are examples of substrate utilization defects. Only four defects of the Krebs cycle are known: fumarase deficiency, dihydrolipoyl dehydrogenase deficiency, alpha-ketoglutarate dehydrogenase deficiency, and combined defects of muscle succinate dehydrogenase and aconitase. Luft disease is the singular example of a defect in oxidation-phosphorylation coupling. Defects of respiratory chain function are manifold. Two clinical syndromes predominate, one involving limb weakness, and the other primarily affecting brain function. Leigh syndrome may result from different enzyme defects, most notably pyruvate dehydrogenase complex deficiency, cytochrome c oxidase deficiency, complex I deficiency, and complex V deficiency associated with the recently described NARP point mutation. A new group of mitochondrial diseases has emerged.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
Affiliation(s)
- D C De Vivo
- Division of Pediatric Neurology, Columbia-Presbyterian Medical Center, New York, NY 10032
| |
Collapse
|
43
|
Dodd PR, Williams SH, Gundlach AL, Harper PA, Healy PJ, Dennis JA, Johnston GA. Glutamate and gamma-aminobutyric acid neurotransmitter systems in the acute phase of maple syrup urine disease and citrullinemia encephalopathies in newborn calves. J Neurochem 1992; 59:582-90. [PMID: 1352800 DOI: 10.1111/j.1471-4159.1992.tb09409.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cerebral cortex tissue was obtained at autopsy from neonatal Poll Hereford calves with clinically confirmed maple syrup urine disease (MSUD), neonatal Holstein-Friesian calves with clinically confirmed citrullinemia, and matched controls. From this, synaptosomes were prepared for studies of neurotransmitter amino acid uptake and stimulus-induced release, and synaptic plasma membranes were obtained for studies of associated postsynaptic receptor binding sites. As well as having abnormal brain tissue concentrations of the pathognomic plasma amino acids (markedly increased levels of the branched-chain compounds valine, isoleucine, and leucine in MSUD; marked elevation of citrulline levels in citrullinemia), both groups of diseased animals showed reduced brain tissue concentrations of each of the transmitter amino acids glutamate, aspartate, and gamma-aminobutyric acid (GABA). Nontransmitter amino acids were generally unaffected in either disease. Citrullinemic calves showed a marked increase in brain glutamine concentration; in calves with MSUD, the glutamine concentration was raised, but to a much lesser extent. The Na(+)-dependent synaptosomal uptake of both glutamate and GABA was markedly reduced (to less than 50% of control values in both cases) in citrullinemic calves but was unaltered in calves with MSUD. Whereas synaptosomes from normal calves showed the expected stimulus-coupled release of transmitter amino acids, especially glutamate and aspartate, and no response to stimulus of nontransmitter amino acids, there was no increased release of transmitter amino acids in response to depolarization in synaptosomes from citrullinemic calves.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- P R Dodd
- Department of Pharmacology, University of Sydney, New South Wales, Australia
| | | | | | | | | | | | | |
Collapse
|
44
|
De Meirleir L, Lissens W, Vamos E, Liebaers I. Pyruvate dehydrogenase (PDH) deficiency caused by a 21-base pair insertion mutation in the E1 alpha subunit. Hum Genet 1992; 88:649-52. [PMID: 1551669 DOI: 10.1007/bf02265291] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We report the molecular characterization of a case of a functional PDH-E1 (E1 subunit of pyruvate dehydrogenase) deficiency, a cause of severe congenital lactic acidosis. Residual PDH-E1 activity was reduced to 10% of normal values, although the subunit appeared to be quantitatively and qualitatively normal at the protein level as determined by Western blotting. The sequence of PDH-E1 alpha mRNA and the corresponding genomic DNA revealed an in-frame 21-bp insertion between codons 305 and 306 of the normal E1 alpha cDNA. The mutational insert commences with a novel GAT codon and is a nearly perfect tandem duplication of the wild type DNA sequence. A serine phosphorylation site regulating the activity of the PDH complex is altered by this insertion, which in all likelihood is responsible for the functional enzymatic deficiency leading to lactic acidosis.
Collapse
Affiliation(s)
- L De Meirleir
- Laboratory of Medical Genetics, Vrije Universiteit Brussel (VUB), Belgium
| | | | | | | |
Collapse
|
45
|
Dahl HH, Hansen LL, Brown RM, Danks DM, Rogers JG, Brown GK. X-linked pyruvate dehydrogenase E1 alpha subunit deficiency in heterozygous females: variable manifestation of the same mutation. J Inherit Metab Dis 1992; 15:835-47. [PMID: 1293379 DOI: 10.1007/bf01800219] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Three female patients are described with pyruvate dehydrogenase (PDH) deficiency as a result of mutation in the X-linked gene for the E1 alpha subunit of the complex. Two of these patients illustrate typical presentations of PDH E1 alpha deficiency, with severe neurological dysfunction, degenerative changes and developmental anomalies in the brain, together with variable lactic acidosis. The third patient extends the known spectrum of the condition to include mild to moderate mental retardation and seizures in an adult. All three patients have the same mutation in the PDH E1 alpha gene. This mutation, a C-to-T substitution in a CpG dinucleotide in amino acid codon 302 (designated R302C), results in the replacement of arginine by cysteine at this position. The mildly affected adult was the mother of one of the other patient, making this the first described instance of mother-to-daughter transmission of a mutation causing PDH E1 alpha deficiency. The genetic basis of the variable expression of X-linked PDH E1 alpha deficiency in heterozygous females is discussed.
Collapse
Affiliation(s)
- H H Dahl
- Murdoch Institute for Research into Birth Defects, Royal Children's Hospital, Melbourne, Australia
| | | | | | | | | | | |
Collapse
|
46
|
Abstract
Pyruvate dehydrogenase (PDH) deficiency has long been recognized as the most common defined cause of primary lactic acidosis in infancy and early childhood. More recently, it has also been described in patients with subacute/chronic neurodegenerative disease without significant metabolic acidosis. The great majority of cases of PDH deficiency result from a genetic defect in the E1 alpha subunit of the complex. PDH E1 alpha deficiency is an X-linked inborn error of metabolism in which a high proportion of heterozygous females manifest the condition. In this review of 29 patients with PDH E1 alpha deficiency, particular emphasis is given to those aspects of the disorder which are specifically related to the X chromosome location of the PDH E1 alpha gene. These include the broad spectrum of clinical presentations and problems of diagnosis, especially antenatal diagnosis, in females.
Collapse
Affiliation(s)
- G K Brown
- Department of Biochemistry, University of Oxford, UK
| |
Collapse
|
47
|
Dahl HH, Brown GK, Brown RM, Hansen LL, Kerr DS, Wexler ID, Patel MS, De Meirleir L, Lissens W, Chun K. Mutations and polymorphisms in the pyruvate dehydrogenase E1 alpha gene. Hum Mutat 1992; 1:97-102. [PMID: 1301207 DOI: 10.1002/humu.1380010203] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We present an update on mutations and polymorphisms in the human X chromosome located pyruvate dehydrogenase E1 alpha gene. A total of 20 different mutations are tabulated. The mutations include deletions, insertions, and point mutations. Certain sequences seem particularly prone to mutation. Most of the mutations are found in exons 10 and 11. Furthermore, four of the mutations are seen in unrelated patients. Little is known about how the mutations affect the structure or function of the pyruvate dehydrogenase complex.
Collapse
Affiliation(s)
- H H Dahl
- Murdoch Institute for Research Into Birth Defects, Royal Children's Hospital, Parkville, Melbourne, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
Characterization of the biochemical basis of various inherited disorders associated with lactic acidosis has increased dramatically in recent years. These include defects of enzymes of gluconeogenesis, pyruvate oxidation, and electron transport. Clinical manifestations of these disorders show great variation and overlap, frequently involving the central nervous system as well as skeletal and cardiac muscle. Several of these enzymes are large complexes of subunits encoded by multiple genes; the electron transport chain complexes include subunits encoded by both nuclear and mitochondrial genes. This great complexity complicates analysis of specific mutations, despite considerable progress in defining the primary structure of component proteins and their genes. With few exceptions, treatment of disorders associated with congenital lactic acidosis remains unsatisfactory.
Collapse
Affiliation(s)
- D S Kerr
- Center for Inherited Disorders of Energy Metabolism, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH 44106
| |
Collapse
|
49
|
Dahl HH, Hutchison WM, Guo Z, Forrest SM, Hansen LL. Polymorphisms in the human X-linked pyruvate dehydrogenase E1 alpha gene. Hum Genet 1991; 87:49-53. [PMID: 1674716 DOI: 10.1007/bf01213091] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pyruvate dehydrogenase E1 alpha deficiency is an X-chromosome-linked disorder, often with fatal consequences. We have searched for genetically useful polymorphisms in or near this gene. No restriction fragment length polymorphisms were detected using a battery of 36 different restriction enzymes and probing with a full-length cDNA fragment, or two single-copy genomic fragments located within intron 8, and 15 kb 3' of the coding region, respectively. The chemical cleavage method was then applied to the detection of base changes in or near the gene. One polymorphism was found in exon 8 of the coding region. However, no base changes were detected in intron 3 or in the part of intron 8 covered by fragment gB2. Three blocks of microsatellite DNA containing variable numbers of CA-repeats were isolated from the 5' end of the gene and characterized. Length polymorphisms in these microsatellite DNAs were analysed using the polymerase chain reaction. Although the three loci are tightly linked, the polymorphisms appear not to be in disequilibrium, making them useful markers in linkage studies of the pyruvate dehydrogenase E1 alpha gene. Of 31 females analysed 12(39%) were heterozygous for at least one length polymorphism of the three (CA)n alleles.
Collapse
Affiliation(s)
- H H Dahl
- Murdoch Institute for Research into Birth Defects, Royal Children's Hospital, Melbourne, Victoria, Australia
| | | | | | | | | |
Collapse
|
50
|
Hansen LL, Brown GK, Kirby DM, Dahl HH. Characterization of the mutations in three patients with pyruvate dehydrogenase E1 alpha deficiency. J Inherit Metab Dis 1991; 14:140-51. [PMID: 1909401 DOI: 10.1007/bf01800586] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The human pyruvate dehydrogenase complex catalyses the oxidative decarboxylation of pyruvate to acetyl-CoA. Defects in several of the seven subunits have been reported, but the majority of mutations affect the E1 component and especially the E1 alpha subunit. However, the clinical presentation of patients with pyruvate dehydrogenase E1 alpha deficiency is extremely variable. Dependency of the brain on pyruvate dehydrogenase activity and localization of the gene for the somatic form of the pyruvate dehydrogenase E1 alpha subunit to the X chromosome provide the basis for a better understanding of the variation in the clinical manifestations. Further understanding of the function and interaction of subunits and the pathophysiology of pyruvate dehydrogenase deficiency necessitates the characterization of mutations in the pyruvate dehydrogenase complex. We report the analysis of three patients with pyruvate dehydrogenase E1 alpha deficiency. One female has a three base pair deletion which affects dephosphorylation of the subunit. Of two males analysed, one has a two base pair deletion causing a shift in the reading frame. The other has a base change, resulting in an Arg to His substitution. All three mutations are located near the carboxyl terminus of the subunit.
Collapse
Affiliation(s)
- L L Hansen
- Murdoch Institute for Research into Birth Defects, Royal Children's Hospital, Melbourne, Victoria, Australia
| | | | | | | |
Collapse
|