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Periventricular Calcification, Abnormal Pterins and Dry Thickened Skin: Expanding the Clinical Spectrum of RMND1? JIMD Rep 2015; 26:13-9. [PMID: 26238252 PMCID: PMC5580737 DOI: 10.1007/8904_2015_479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND We report a consanguineous Sudanese family whose two affected sons presented with a lethal disorder characterised by severe neonatal lactic acidosis, hypertonia, microcephaly and intractable seizures. One child had additional unique features of periventricular calcification, abnormal pterins and dry thickened skin. METHODS Exome enrichment was performed on pooled genomic libraries from the two affected children and sequenced on an Illumina HiSeq2000. After quality control and variant identification, rare homozygous variants were prioritised. Respiratory chain complex activities were measured and normalised to citrate synthase activity in cultured patient fibroblasts. RMND1 protein levels were analysed by standard Western blotting. RESULTS Exome sequencing identified a previously reported homozygous missense variant in RMND1 (c.1250G>A; p.Arg417Gln), the gene associated with combined oxidation phosphorylation deficiency 11 (COXPD11), as the most likely cause of this disorder. This finding suggests the presence of a mutation hotspot at cDNA position 1250. Patient fibroblasts showed a severe decrease in mitochondrial respiratory chain complex I, III and IV activities and protein expression, albeit with normal RMND1 levels, supporting a generalised disorder of mitochondrial translation caused by loss of function. CONCLUSIONS The current study implicates RMND1 in the development of calcification and dermatological abnormalities, likely due to defective ATP-dependent processes in vascular smooth muscle cells and skin. Review of reported patients with RMND1 mutations shows intra-familial variability and evidence of an evolving phenotype, which may account for the clinical variability. We suggest that COXPD11 should be considered in the differential for patients with calcification and evidence of a mitochondrial disorder.
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Zecic A, Smet JE, Praeter CMD, Vanhaesebrouck P, Viscomi C, Broecke CVD, Paepe BD, Lohse P, Martin JJ, Jackson JG, Campbell CR, Meirleir LJD, Zeviani M, Seneca SH, Lissens W, Coster RNV. Lactic acidosis in a newborn with adrenal calcifications. Pediatr Res 2009; 66:317-22. [PMID: 19581830 PMCID: PMC7101825 DOI: 10.1203/pdr.0b013e3181b40a80] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A patient is reported who presented in the newborn period with an unusual combination of congenital lactic acidosis and bilateral calcifications in the adrenal medulla, visible on standard abdominal x-ray and ultrasound examination. At birth, the proband was hypotonic and dystrophic. She developed respiratory insufficiency, cardiomegaly, and hepatomegaly and died at the age of 38 d. Examination of postmortem heart muscle revealed multiple areas of myocardial infarction with dystrophic calcifications. In the medulla of the adrenal glands, foci of necrosis and calcifications, and in the liver, multiple zones of necrosis and iron deposition were detected. Biochemical analysis in heart muscle revealed a decreased activity of complex IV of the oxidative phosphorylation (OXPHOS) and in liver a combined deficiency involving the complexes I, III, IV, and V. The findings were suggestive of a defect in biosynthesis of the mitochondrially encoded subunits of the OXPHOS complexes. Extensive analysis of the proband's mitochondrial DNA revealed neither pathogenic deletions and point mutations nor copy number alterations. Relative amounts of mitochondrial transcripts for the ribosomal mitochondrial 12S rRNA (12S) and mitochondrial 16S rRNA (16S) were significantly increased suggesting a compensatory mechanism involving the transcription machinery to low levels of translation. The underlying molecular defect has not been identified yet.
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Affiliation(s)
- Alexandra Zecic
- Departments of Neonatology, Ghent University Hospital, Ghent, 9000 Belgium
| | - Joél E Smet
- Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, 9000 Belgium
| | | | | | - Carlo Viscomi
- Department of Molecular Neurogenetics, Istituto Nazionale Neurologico “C. Besta,”, Milan, 20126 Italy
| | | | - Boel De Paepe
- Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, 9000 Belgium
| | - Peter Lohse
- Department of Clinical Chemistry, University of Munich, Munich, 81377 Germany
| | | | - Joshua G Jackson
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455
| | - Colin R Campbell
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455
| | - Linda J De Meirleir
- Department of Medical Genetics, University Hospital Brussels, Brussels, 1090 Belgium
| | - Massimo Zeviani
- Department of Molecular Neurogenetics, Istituto Nazionale Neurologico “C. Besta,”, Milan, 20126 Italy
| | - Sara H Seneca
- Department of Medical Genetics, University Hospital Brussels, Brussels, 1090 Belgium
| | - Willy Lissens
- Department of Medical Genetics, University Hospital Brussels, Brussels, 1090 Belgium
| | - Rudy N Van Coster
- Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, 9000 Belgium
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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.
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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
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Briones P, Vilaseca MA, Ribes A, Vernet A, Lluch M, Cusi V, Huckriede A, Agsteribbe E. A new case of multiple mitochondrial enzyme deficiencies with decreased amount of heat shock protein 60. J Inherit Metab Dis 1997; 20:569-77. [PMID: 9266394 DOI: 10.1023/a:1005303008439] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Heat shock protein 60 (hsp60) is a mitochondrial matrix protein involved in the folding and correct assembly of polypeptides into complex mitochondrial enzymes. Its deficiency has recently been described as the most likely primary cause of congenital lactic acidaemia with multiple mitochondrial enzyme deficiencies in a female patient. We describe a new case of a girl with a substantially decreased amount of hsp60 in cultured fibroblasts. She presented from birth with hypotonia, unusual facial features, feeding difficulties and failure to thrive. Death occurred at age 4.5 years. Biochemical findings included metabolic acidosis with lactic acidaemia, hyperammonaemia and intermittent ketosis. In contrast to the previously reported case, organic acid analysis showed an altered profile throughout her life. In agreement with this profile, various mitochondrial enzyme activities were deficient in cultured fibroblasts, including enzymes of the respiratory chain and the Krebs cycle, the pyruvate dehydrogenase complex and the mitochondrial biotindependent carboxylases. Fibroblast mitochondria showed ultrastructural abnormalities, were swollen, and were mainly localized around the nucleus. The description of a second case of multiple mitochondrial enzyme deficiencies with reduced amount of hsp60 supports the idea that hsp60 deficiency might be a more common cause of mitochondrial disease. This opens new possibilities for the diagnosis and understanding of congenital lactic acidaemia.
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Affiliation(s)
- P Briones
- Institut de Bioquímica Clínica, Corporació Sanitària i CSIC, Barcelona, Spain
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5
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Barogi S, Baracca A, Parenti Castelli G, Bovina C, Formiggini G, Marchetti M, Solaini G, Lenaz G. Lack of major changes in ATPase activity in mitochondria from liver, heart, and skeletal muscle of rats upon ageing. Mech Ageing Dev 1995; 84:139-50. [PMID: 8788241 DOI: 10.1016/0047-6374(95)01640-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
ATP hydrolase activity has been investigated in mitochondria from liver, heart, and skeletal muscle from adult (6 months) and aged (24 months) rats. No significant changes in total ATPase activity were observed in the three tissues, but the oligomycin sensitivity was slightly decreased in heart mitochondria of aged rats. The bicarbonate-induced stimulation of hydrolytic activity was somewhat decreased in mitochondria from aged rats, particularly in liver. No significant change was observed in ATPase activity after release of the endogenous inhibitor protein, IF1. It is concluded that no activity changes to be directly ascribed to the catalytic sector F1 of the enzyme occur upon ageing, but it cannot be excluded that changes in the membrane sector F0 occur as a consequence of mtDNA mutations.
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MESH Headings
- Adenosine Triphosphatases/drug effects
- Adenosine Triphosphatases/metabolism
- Aging/metabolism
- Animals
- Male
- Mitochondria, Heart/drug effects
- Mitochondria, Heart/enzymology
- Mitochondria, Liver/drug effects
- Mitochondria, Liver/enzymology
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/enzymology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/ultrastructure
- Oligomycins/pharmacology
- Rats
- Rats, Wistar
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Affiliation(s)
- S Barogi
- Dipartimento di Biochimica G. Moruzzi, University of Bologna, Italy
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6
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Huckriede A, Heikema A, Sjollema K, Briones P, Agsteribbe E. Morphology of the mitochondria in heat shock protein 60 deficient fibroblasts from mitochondrial myopathy patients. Effects of stress conditions. Virchows Arch 1995; 427:159-65. [PMID: 7582246 DOI: 10.1007/bf00196521] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have described two mitochondrial (mt) myopathy patients with reduced activities of various mt enzymes associated with significantly decreased amounts of heat shock protein 60 (hsp60). Experimental evidence suggested that the lack of hsp60 was the primary defect. Since hsp60 is essential for the proper folding of enzyme subunits in the mt matrix a partial deficiency of this protein can explain the observed defects of the mitochondria. Here we report on morphological studies aimed at obtaining more insight into the relation between lack of hsp60 and pathological changes of the mitochondria. Under standard culture conditions mitochondria in the partially hsp60 deficient fibroblasts showed profound morphological aberrations. In contrast, the mitochondria in fibroblasts from a MELAS patient and a cytochrome c oxidase-deficient patient appeared normal. Under stress conditions the integrity of the hsp60 deficient mitochondria declined even further: heat shock induced a temporary collapse of the electrochemical potential across the inner mt membrane, but did not affect the ultrastructure of the mitochondria; prolonged growth in confluent cultures resulted in decrease in mt number. The altered mt morphology in the hsp60 deficient cells is probably indicative of the severely impaired mt metabolism whereas the decreased stress tolerance is likely to be a direct result of paucity of the heat shock protein. Both variables are potentially useful in the diagnosis and molecular characterization of mt disorders with systemic manifestation and multiple enzyme deficiency.
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Affiliation(s)
- A Huckriede
- Department of Physiological Chemistry, University of Groningen, The Netherlands
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Samson JF, Barth PG, de Vries JI, Menko FH, Ruitenbeek W, van Oost BA, Jakobs C. Familial mitochondrial encephalopathy with fetal ultrasonographic ventriculomegaly and intracerebral calcifications. Eur J Pediatr 1994; 153:510-6. [PMID: 7957369 DOI: 10.1007/bf01957007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In two sibs antenatal ultrasonography revealed identical intracranial calcification, ventricular widening and microcephaly. The first pregnancy was artificially terminated at 19 weeks. Post-mortem examination of the brain revealed destructive calcification and extracerebral neuronal heterotopia. The second sib went to term but died 48 h after birth from irreversible lactic acidosis. Autopsy showed extensive encephalopathy with cavitation and calcification in the cerebral hemispheres, polymicrogyria, multiple neuronal heterotopia, partial callosal dysgenesis, and severe Leigh syndrome, together forming a continuum of early and late brain disruption. Mitochondrial respiratory chain abnormalities, mainly affecting complexes I and IV, and deficiency of pyruvate dehydrogenase complex were detected in skeletal muscle and in liver. A normal functioning of the respiratory chain was found in the fibroblasts. Analysis of mtDNA from muscle, liver and blood revealed normal amounts of intact mtDNA without any of the known point mutations associated with MELAS, MERRF or Leigh syndromes. The early fetal disruption and necrotic changes in the brains of sibs indicate a specific genetically determined disorder which affects neuronal migration, a finding not previously associated with respiratory chain disorders. The present disorder may mimic antenatal congenital infectious encephalopathy because of the combined finding of microcephaly and destructive intracerebral calcification.
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Affiliation(s)
- J F Samson
- Department of Paediatrics, Free University Hospital, Amsterdam, The Netherlands
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Robinson BH. MtDNA and nuclear mutations affecting oxidative phosphorylation: correlating severity of clinical defect with extent of bioenergetic compromise. J Bioenerg Biomembr 1994; 26:311-6. [PMID: 8077184 DOI: 10.1007/bf00763102] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rates of ATP synthesis were studied in cultured skin fibroblasts treated with digitonin. In fibroblasts from patients with complex I deficiency, complex IV and complex V deficiency rates of ATP synthesis were decreased below the levels found in controls. In mitochondria isolated from cultured lymphoblasts, ATP synthesis was also decreased by 35-50% in cases of Leigh's disease due to complex I, complex IV, or complex V deficiency. Calculating the effect of the mutations in the various complexes on the overall efficiency of oxidative phosphorylation, we show that the mtDNA 8993 mutation which affects the activity of the F1F0 ATPase (complex V) has the strongest effect.
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Affiliation(s)
- B H Robinson
- Department of Biochemistry, University of Toronto, Ontario, Canada
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9
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Das AM, Schweitzer-Krantz S, Byrd DJ, Brodehl J. Absence of cytochrome c oxidase activity in a boy with dysfunction of renal tubules, brain and muscle. Eur J Pediatr 1994; 153:267-70. [PMID: 8194561 DOI: 10.1007/bf01954517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We report on a boy who developed proximal renal tubular acidosis with loss of carnitine at the age of about 6 months. A few months later he began to suffer from progressive muscular weakness and neurological disturbances. Blood biochemistry showed elevated lactate and beta-hydroxybutyrate with increased lactate/pyruvate and beta-hydroxybutyrate/acetoacetate ratios. A high urinary excretion of lactate and citric acid cycle intermediates was found. These results indicated a defect of the mitochondrial respiratory chain. Analysis of biopsy material from skeletal muscle revealed low activities of all respiratory chain complexes. In muscle and fibroblasts cytochrome c-oxidase (complex IV) was absent. Despite high dose multi-vitamin therapy the boy died at the age of 30 months from central respiratory failure. At autopsy the neuropathological diagnosis of Leigh disease was made.
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Affiliation(s)
- A M Das
- Department of Paediatric Nephrology and Metabolic Disorders, Children's Hospital, Hannover Medical School, Germany
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10
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Affiliation(s)
- B H Robinson
- Department of Biochemistry, University of Toronto, Ontario, Canada
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11
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Christodoulou J, Petrova-Benedict R, Robinson BH, Jay V, Clarke JT. An unusual patient with the neonatal Marfan phenotype and mitochondrial complex I deficiency. Eur J Pediatr 1993; 152:428-32. [PMID: 8319712 DOI: 10.1007/bf01955904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We report the case of a 16-month-old male with the neonatal appearance of Marfan syndrome (NMS), with dolichocephaly, a long midface, deep-set eyes, arachnodactyly, dislocated lenses and carciovascular abnormalities. The presence of persistent lactic acidosis led to studies which disclosed mitochondrial complex I deficiency. We speculate that this unusual association may be due to the combination of an inherited mutation affecting complex I activity along with a de novo mutation disrupting the corresponding locus and an adjacent NMS locus on the homologous autosome. The possibility that the phenotype observed in this patient is directly due to the mitochondrial defect cannot be excluded.
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Affiliation(s)
- J Christodoulou
- Division of Clinical Genetics, Hospital for Sick Children, Toronto, Canada
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