Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029089 (ophthalmoplegia)
 3,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since the first identification in 1988 of pathogenic mitochondrial DNA (mtDNA) mutations, the mitochondrial diseases have emerged as a major clinical entity. The most striking feature of these disorders is their marked heterogeneity, which extends to their clinical, biochemical, and genetic characteristics. The major mitochondrial encephalomyopathies include MELAS (mitochondrial encephalopathy with lactic acidosis and stroke-like episodes), MERRF (myoclonic epilepsy with ragged red fibers), KSS/CPEO (Kearns-Sayre syndrome/chronic progressive external ophthalmoplegia), and NARP/MILS (neuropathy, ataxia, and retinitis pigmentosum/maternally inherited Leigh syndrome) and they typically present highly variable multisystem defects that usually involve abnormalities of skeletal muscle and/or the CNS. The primary emphasis here is to review recent investigations of these mitochondrial diseases from the standpoint of how the complexities of mitochondrial genetics and biogenesis might determine their varied features. In addition, the mitochondrial encephalomyopathies are compared and contrasted to Leber hereditary optic neuropathy, a mitochondrial disease in which the pathogenic mtDNA mutations produce a more uniform and focal neuropathology. All of these disorders involve, at some level, a mitochondrial respiratory chain dysfunction. Because mitochondrial genetics differs so strikingly from the Mendelian inheritance of chromosomes, recent research on the origin and subsequent segregation and transmission of mtDNA mutations is reviewed.
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PMID:Human mitochondrial diseases: answering questions and questioning answers. 977 Feb 97

We have examined the transcript levels of a variety of oxidative phosphorylation (OXPHOS) and associated bioenergetic genes in tissues of a patient carrying the myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) A3243G mitochondrial DNA (mtDNA) mutation and the skeletal muscles of 14 patients harboring other pathogenic mtDNA mutations. The patients' tissues, which harbored 88% or more mutant mtDNA, had increased levels of mtDNA transcripts, increased nuclear OXPHOS gene transcripts including the ATP synthase beta subunit and the heart-muscle isoform of the adenine nucleotide translocator, and increased ancillary gene transcripts including muscle mitochondrial creatine phosphokinase, muscle glycogen phosphorylase, hexokinase I, muscle phosphofructokinase, the E1alpha subunit of pyruvate dehydrogenase, and the ubiquinone oxidoreductase. A similar coordinate induction of bioenergetic genes was observed in the muscle biopsies of severe pathologic mtDNA mutations. The more significant coordinated expression was found in muscle from patients with the MELAS, myoclonic epilepsy with ragged red fibers, and chronic progressive external ophthalmoplegia deletion syndromes, with ragged red muscle fibers and mitochondrial paracrystalline inclusions. High levels of mutant mtDNAs were linked to a high induction of the mtDNA and nuclear OXPHOS genes and of several associated bioenergetic genes. These observations suggest that human tissues attempt to compensate for OXPHOS defects associated with mtDNA mutations by stimulating mitochondrial biogenesis, possibly mediated through redox-sensitive transcription factors.
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PMID:Coordinate induction of energy gene expression in tissues of mitochondrial disease patients. 1043 62

Two rare cases of Wernicke's encephalopathy (WE) in non-alcoholic patients on hemodialysis (HD) are reported. They presented with the clinical triad of WE (ophthalmoplegia, ataxia and disturbance of consciousness) and intravenous administration of thiamine led to complete elimination of these manifestations. Reduced plasma thiamine levels prior to the administration confirmed the diagnosis of WE. Interestingly, a reduction in plasma thiamine levels by about half was seen in one of the patients on HD, suggesting that thiamine, a water-soluble vitamin, can be depleted with HD. In the literature, nine HD-dependent patients have been reported to develop WE, seven of whom were diagnosed postmortem. Their premortem diagnoses included uremic encephalopathy, dysequilibrium syndrome and dialysis dementia, which can often complicate HD and present symptoms similar to those of WE. We therefore emphasize that WE, even though a rare complication, should be suspected in all patients on HD who present with at least one of the clinical triad of WE.
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PMID:Wernicke's encephalopathy associated with hemodialysis: report of two cases and review of the literature. 1046 8

Five unrelated patients harboring the A3243G mutation in the mitochondrial DNA (mtDNA) but presenting with different clinical phenotype were studied for their percentage of mutation at the single muscle fiber levels. One patient had a clinically and pathologically defined Leigh syndrome (LS), two showed mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), another showed progressive external ophthalmoplegia (PEO), and the other showed mitochondrial diabetes mellitus (MDM). The mutation load was greater in the muscle from the patient with LS (92%), who showed more than 80% even in the non-ragged red fibers (RRF) and also presented the highest proportion of RRF. The patients with MELAS had lower mutation levels as well as a lower proportion of RRF, and these two parameters were even lower in the PEO and MDM patients. These results were consistent with the concept that differences in the mutation load and in the somatic distribution of the mutation among different cells and tissues are responsible for the differences in phenotypical expression of the disease.
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PMID:Single-fiber analysis of mitochondrial A3243G mutation in four different phenotypes. 1067 26

Much interest has recently been shown in apoptosis-mediated roles in the pathophysiology of mitochondrial diseases, because mitochondrial defects are implicated in a wide variety of degenerative diseases. We investigated whether apoptotic events occurred in skeletal muscles of patients with mitochondrial diseases, including chronic progressive external ophthalmoplegia (CPEO), Kearns-Sayer syndrome (KSS), and mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). In a immunohistochemical study, stainings for 8-hydroxy-deoxyguanosine (8-OH-dG), 4-hydroxy-nonenal (4-HNE), Mn-SOD, Bcl-2, cytochrome c, DNase I and Bcl-x L showed a pronounced granular distribution in the cytochrome c oxidase (COX)-negative ragged-red fibers (RRFs). On the other hand, the signals for Bax, p53, Fas and caspase 3 were not obviously increased in RRFs. In situ labeling of DNA breaks demonstrated preferential signals not only in myonuclei but also in subsarcolemmal regions of RRFs, indicating that mitochondrial as well as myonuclear DNA is fragmented in RRFs. An immunoblotting study demonstrated that cytochrome c was increased in the cytosol of diseased muscles and that DNase I was increased in mitochondria, compared to that of normal muscles. No difference was observed between protein bands at 20 kDa corresponding to caspase 3 in diseased and normal muscles. These findings demonstrate that these mitochondrial diseases harbor unique apoptosis-related changes that differ from caspase 3-dependent apoptosis. It is thought that these changes are induced by superoxide overproduction and cytochrome c release resulting from an inherent mitochondrial defect and that the events are associated with DNase I activation.
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PMID:Apoptosis-related changes in skeletal muscles of patients with mitochondrial diseases. 1181 Jan 83

The Kearns-Sayre syndrome (characterized by onset before 20, chronic ophthalmoplegia, pigmentary retinal degeneration and at least 1 of the following symptoms: ataxia, heart block and high protein content in the cerebrospinal fluid) is a severe variant of chronic progressive external ophthalmoplegia (CPEO) with frequent re-arrangements of the mitochondrial DNA (mtDNA). The aim of this paper is to report a sporadic paediatric case of Kearns-Sayre syndrome with mtDNA heteroplasmic deletion, absence of cytochrome c oxidase in many muscle fibers, autoimmune thyroiditis followed by depressive phobic disturbances, slowing EEG, hyperreflexia, tremor and visual hallucinations, in which the diagnosis of possible encephalopathy associated with autoimmune thyroid disease (Hashimoto encephalopathy) was made. We speculated that in this patient, predisposed by mitochondrial deletion, anti-thyroid antibodies may have interfered with mitochondrial cerebral function, causing Hashimoto encephalopathy and facilitating ophthalmoplegia. It seems important to study anti-thyroid antibodies in every case of Kearns-Sayre syndrome, specially if ophthalmoplegia is recent, even in order to the therapy.
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PMID:A case of Kearns-Sayre syndrome with autoimmune thyroiditis and possible Hashimoto encephalopathy. 1209 44

We present the current knowledge on the genetic and phenotypic aspects of mitochondrial DNA depletion syndromes. The human mitochondrial DNA encodes 13 of the 82 structural proteins of the mitochondrial electron transport chain. The replication and maintenance of the mtDNA require a large number of nuclear encoded enzymes and balanced nucleotide pools. Mitochondrial nucleotide synthesis is of major importance because of the constant need for nucleotides for mtDNA maintenance even in quiescent cells. As de novo enzymes are not present in the mitochondria, synthesis is accomplished via the salvage pathway. Defective mtDNA synthesis and maintenance manifest by multiple deletions or by depletion of the mitochondrial genome. Patients with multiple deletions typically present with progressive external ophthalmoplegia, ptosis and, exercise intolerance after the first decade of life. mtDNA depletion is usually an infantile disease characterized by severe muscle weakness, hepatic failure, or renal tubulopathy with fatal outcome. Linkage analysis in families with multiple mtDNA deletions reveal mutations in proteins that participate in mtDNA replication, the mitochondrial DNA polymerase gene, and the Twinkle gene, a putative mitochondrial helicase and in factors which play a role in mitochondrial nucleotide metabolism, the adenine nucleotide translocator, and the thymidine phosphorylase gene. We have recently identified mutations in an additional two essential proteins in the nucleotide salvage pathway, the mitochondrial deoxyribonucleoside kinases. The phenotype was distinctive for each gene, with hepatic failure and encephalopathy associated with mutations in the deoxyguanosine kinase gene and isolated devastating myopathy as the sole manifestation of thymidine kinase 2 deficiency. The tissue selectivity of these disorders and especially the exclusive muscle involvement in thymidine kinase 2 mutations is puzzling. The normal sequence of the remaining mtDNA copies in spite of a serious mitochondrial nucleotide imbalance is also unexpected. We propose several tissue-specific protective mechanisms and a time window, likely encompassing fetal life and even early infancy, during which nuclear nucleotide synthesis provides mitochondrial needs in all organs. We also speculate on future genes to be discovered in other phenotypes of mtDNA depletion.
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PMID:Depletion of the other genome-mitochondrial DNA depletion syndromes in humans. 1211 Sep 44

Hemodialysis(HD) patients are at risk for thiamine deficiency because of low intake and accelerated loss of thiamine during HD. We report here an HD patient, an 82-year-old woman, who developed acute encephalopathy due to thiamine deficiency with hyperammonemia. She was admitted to Nishikawa Town Hospital due to pneumonia and was treated with ABPC/SBT for one week. While she was cured of pneumonia, she had a persistently poor appetite. On the twenty-fourth day after admission, HD with intradialytic parenteral nutrition(IDPN), which consisted of 10% glucose 500 ml, in order to correct her malnutrition, was started. She suddenly presented confusion, speech disturbance and ophthalmoplegia. HD with IDPN was stopped after two hours because of her symptoms. Laboratory studies disclosed plasma glucose of 186 mg/dl and serum ammonium of 155 micrograms/dl. Arterial blood gas analysis(inhaling 3 l/min O2) showed severe metabolic acidosis and respiratory acidosis (pH 7.138, pCO2 44.8 mmHg, pO2 108.9 mmHg, HCO3- 15.1 mmol/l). Her malnutrition, unexplained metabolic acidosis and neurological presentation raised the suspicion of acute encephalopathy due to thiamine deficiency. Fursultiamine 100 mg was administered intravenously. After two hours, metabolic acidosis disappeared (pH 7.437, pCO2 33.9 mmHg, pO2 161.0 mmHg, HCO3- 22.9 mmol/l), and she regained her clear consciousness and serum ammonium decreased at 16 micrograms/dl on the next morning. Serum lactate and thiamine level were shown later to be 57.5 mg/dl and 27 nmol/l, respectively. Her clinical course suggests that the glucose load including IDPN may have caused deterioration of the neurological disorder under the condition of thiamine deficiency. Furthermore, it is possible that a relationship exists between thiamine deficiency and hyperammonemia.
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PMID:[Acute encephalopathy due to thiamine deficiency with hyperammonemia in a chronic hemodialysis patient: a case report]. 1280 78

We report a novel, heteroplasmic point mutation in the mitochondrial tRNA for tryptophan at position 5532. The mutation was present in all the tissues studied and segregated with the biochemical defect, with higher levels of mutation present in cytochrome c oxidase-deficient muscle fibres. The patient manifested a neurogastrointestinal syndrome with features including failure to thrive, psychomotor retardation, ophthalmoplegia, sensorineural deafness and encephalopathy together with vomiting, diarrhoea and colitis.
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PMID:A novel point mutation in the mitochondrial tRNA(Trp) gene produces a neurogastrointestinal syndrome. 1505 99

The 3243A > G mutation is one of the most frequently observed mutations of mitochondrial DNA (mtDNA), and is associated with numerous clinical presentations including mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), progressive external ophthalmoplegia (PEO) and diabetes and deafness. The routine diagnosis of the 3243A > G mutation in blood is difficult as mutation levels are known to decrease in this tissue over time, while in some patients it may be absent. We have directly compared the levels of the 3243A > G mutation in skeletal muscle, blood and urinary epithelial cells in 18 patients and observed a striking correlation between the mutation load in postmitotic muscle and urinary epithelium, a mitotic tissue. These data strongly support the use of urinary epithelial cells as the tissue of choice in the noninvasive diagnosis of the 3243A > G mutation.
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PMID:Noninvasive diagnosis of the 3243A > G mitochondrial DNA mutation using urinary epithelial cells. 1519 81


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