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Query: UMLS:C0751651 (mitochondrial disease)
 1,844 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Over the past 13 years at VGH-Taipei, five cases were morphologically defined as having mitochondrial disease and clinically presented with syndromes other than chronic progressive external ophthalmoplegia. There were two cases presenting with dementia, extensive and symmetrical intracerebral calcification but no clinical and other laboratory evidence of skeletal muscle affection; one case with MERRF syndrome; one case with congenital myopathy and cardiomyopathy; and one case with prednisolone-responsive and polymyositis-like myopathy. The following comments are made: 1. The inexplicably lower incidence of encephalopathy group might result from inadequate alertness of clinicians. 2. The clinical classification might have some clinical convenience, but, identification of defects at the DAN level and determination of the phenotypic expression with clinical, morphologic and biochemical methods are fundamental for future rational diagnosis and classification of mitochondrial diseases.
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PMID:Mitochondrial disease with encephalopathy or limb girdle myopathy: a report of five cases. 817 14

We studied a 5-year-old boy with mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike episodes that are characteristic of the MELAS syndrome. Results of biochemical, histopathological, and molecular genetic studies from the patient's tissue meet the criteria for diagnosis of mitochondrial disease. An A to G transition at the 3243th nucleotide position of mitochondrial DNA (mtDNA) was found in the blood cells and hair follicles, instead of in muscle, from the propositus. To the best of our knowledge, this is the first reported MELAS case associated with mtDNA mutation in blood cells and hair follicles, instead of in the target muscle tissue, that has ever been documented in Taiwan. Brain lesions demonstrated by angiography, computed tomography (CT) and magnetic resonance imaging (MRI) are discussed.
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PMID:Mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike episodes (MELAS): report of a sporadic case and review of the literature. 818 91

Defects of the respiratory chain carrying out oxidative phosphorylation (OXPHOS) are the biochemical hallmark of human mitochondrial disorders. Faulty OXPHOS can be due to mutations in either nuclear or mitochondrial genes, that are involved in the synthesis of individual respiratory subunits or in their post-translational control. The most common mitochondrial disorder of infancy and childhood is Leigh's syndrome, a severe encephalopathy, often associated with a defect of cytochrome c oxidase (COX). In order to demonstrate which genome is primarily involved in COX-deficient (COX(-))-Leigh's syndrome, we generated two lines of transmitochondrial cybrids. The first was obtained by fusing nuclear DNA-less cytoplasts derived from normal fibroblasts, with mitochondrial DNA-less (rho degree) transformant fibroblasts derived from a patient with COX(-))-Leigh's syndrome. The second cybrid line was obtained by fusing rho degree cells derived from 143B.TK- human osteosarcoma cells, with cytoplasts derived from the same patient. The first cybrid line showed a specific and severe COX(-) phenotype, while in the second all the respiratory chain complexes, including COX, were normal. These results indicate that the COX defect in our patient is due to a mutation of a nuclear gene. The use of cybrids obtained from 'customized', patient-derived rho degree cells can have wide applications in the identification of respiratory chain defects originated by nuclear DNA-encoded mutations, and in the study of nuclear DNA-mitochondrial DNA interactions.
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PMID:Nuclear DNA origin of cytochrome c oxidase deficiency in Leigh's syndrome: genetic evidence based on patient's-derived rho degrees transformants. 858 77

Migraine and the MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) syndrome have some clinical features in common. First, cerebral infarctions, most often in the posterior cerebral regions, which are a main symptom of MELAS, may complicate migraine. Second, migrainous headache with vomiting is also a characteristic feature of the MELAS syndrome. Less frequently, hemicranial headache is present in another mitochondrial disease, myoclonic epilepsy with ragged-red fibers (MERRF). Moreover, there is a mild bias toward maternal transmission in migraine. Apart from clinical resemblance, there is some experimental evidence for mitochondrial dysfunction in migraine. There may be depression of respiratory chain enzyme activity in muscle and platelets, and magnetic resonance spectroscopy has revealed a defective energy metabolism in brain and muscle of migraine patients. There has not been a systematic study of mitochondrial DNA in migraine, however. We therefore analyzed the mitochondrial DNA in lymphocytes of 23 migraine patients with aura. Southern blot and polymerase chain reaction analysis of mitochondrial DNA failed to detect any large-scale deletions or point mutations at base pair 3243 (MELAS) and base pair 8344 (MERRF). Our data show that deletions of mitochondrial DNA and the most frequent point mutations of MELAS and MERRF syndromes are not common in migraine with aura. In particular, these data do not support the hypothesis that some cases of migraine may be monosymptomatic forms of a MELAS syndrome. We cannot exclude, however, that migraine may be associated with different point mutations of mitochondrial DNA or with mutations of autosomally coded respiratory chain subunit genes.
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PMID:Mitochondrial DNA in migraine with aura. 864 80

Mitochondrial encephalomyopathy is a hereditary syndrome showing impairment of muscle and the central nervous system. In this disorder, the following three syndromes have been identified on the basis of characteristic symptoms: Kearns-Sayre syndrome (KSS), mitochondrial encephalomyopathy with lactic acidosis, and stroke-like episodes (MELAS), and myotonic epilepsy with ragged-red fibers (MERRF). In this report, we describe a case of mitochondrial encephalomyopathy with renal disease. A 25-year-old man was referred to our hospital in May, 1992 for evaluation of long-standing proteinuria. He had a small stature, exotropia and no pretibial edema. No mental retardation was observed. Urinary protein excretion was 2.0 g/day and urine sugar was negative. Laboratory examination revealed a serum urea nitrogen 19 mg/dl, and a creatinine value of 1.5 mg/dl. Creatinine clearance was 45.8 ml/min. His serum and spinal fluid lactate value were elevated. Biopsied muscle showed an absence of ragged-red fibers, and the presence of an A-to-G point mutation at nucleotide pari 3243 in the mitochondrial tRNA(Leu(UUR)) in peripheral blood leucocytes. He was thought to have MELAS. On the renal biopsy specimens, light microscopic examinations showed minor glomerular abnormalities with two glomerular collapses and tubulo-interstitial damage. Electron microscopic examinations showed partial thickening of the glomerular basement membrane. We report here this rare case of MELAS with renal disease, and also review seventeen cases of mitochondrial encephalopathy associated with renal disease. The existence of a relationship between mitochondrial disorder and renal damage remains obscure.
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PMID:[A case of mitochondrial encephalomyopathy (MELAS)]. 871 14

We describe a childhood mitochondrial disorder in which the clinical symptoms began and remained confined to the gastrointestinal (GI) system during the first 4 y. Seizures heralded the onset of progressive encephalopathy at age 7. Peripheral neuropathy, retinitis pigmentosa, and neural deafness developed subsequently. Laboratory investigations disclosed elevated levels of plasma lactate, and a muscle biopsy revealed ragged red fibers lacking cytochrome c oxidase activity and diminished levels of respiratory chain enzyme complexes. Molecular genetic tests failed to show any of the previously reported pathogenic mitochondrial DNA (mtDNA) mutations. We therefore screened the whole mitochondrial genome by coupling restriction digestions with single-strand conformational polymorphism (SSCP) patterns. We identified a unique SSCP in the segment that encompassed the tRNA(Lys) gene, and direct sequencing of this segment revealed a G-->A transition at an evolutionarily conserved nucleotide at mtDNA position 8313. This G8313A transition was heteroplasmic in muscle and fibroblasts of the patient, but was absent in the white blood cells and platelets from his maternal relatives. This report illustrates how GI symptoms can be the initial manifestation in a mitochondrial disorder and suggests that mitochondrial dysfunction should be considered in differentials of unexplained chronic GI symptoms, especially when lactic acidosis or other unrelated clinical signs or symptoms are present.
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PMID:A novel mitochondrial G8313A mutation associated with prominent initial gastrointestinal symptoms and progressive encephaloneuropathy. 938 Apr 35

Defects of the mitochondrial respiratory chain are associated with a great variety of clinical disorders. In addition to the well recognized syndromes, a significant number of patients present non-specific encephalopathic disorders. In consequence these types of mitochondrial disorder are very difficult to diagnose on clinical features alone. In this paper, we describe the clinical and the magnetic resonance findings of 2 patients with a neurological syndrome indistinguishable from multiple sclerosis (Poser). Muscle biochemistry revealed defect of complex IV of the respiratory chain. We think that these patients have a mitochondrial encephalomyopathy. We suggest that in patients presenting as atypical multiple sclerosis it could be necessary investigating mitocondrial encephalopathy.
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PMID:[Mitochondrial respiratory chain deficiency may present as multiple sclerosis]. 960 60

We have identified the first stop-codon point mutation in mtDNA to be reported in association with human disease. A 36-year-old woman experienced episodes of encephalopathy accompanied by lactic acidemia and had exercise intolerance and proximal myopathy. Histochemical analysis showed that 90% of muscle fibers exhibited decreased or absent cytochrome c oxidase (COX) activity. Biochemical studies confirmed a severe isolated reduction in COX activity. Muscle immunocytochemistry revealed a pattern suggestive of a primary mtDNA defect in the COX-deficient fibers and was consistent with either reduced stability or impaired assembly of the holoenzyme. Sequence analysis of mtDNA identified a novel heteroplasmic G-->A point mutation at position 9952 in the patient's skeletal muscle, which was not detected in her leukocyte mtDNA or in that of 120 healthy controls or 60 additional patients with mitochondrial disease. This point mutation is located in the 3' end of the gene for subunit III of COX and is predicted to result in the loss of the last 13 amino acids of the highly conserved C-terminal region of this subunit. It was not detected in mtDNA extracted from leukocytes, skeletal muscle, or myoblasts of the patient's mother or her two sons, indicating that this mutation is not maternally transmitted. Single-fiber PCR studies provided direct evidence for an association between this point mutation and COX deficiency and indicated that the proportion of mutant mtDNA required to induce COX deficiency is lower than that reported for tRNA-gene point mutations. The findings reported here represent only the second case of isolated COX deficiency to be defined at the molecular genetic level and reveal a new mutational mechanism in mitochondrial disease.
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PMID:Cytochrome c oxidase deficiency associated with the first stop-codon point mutation in human mtDNA. 963 11

Kearns-Sayre syndrome (KSS) is a mitochondrial disorder. There is a large-scale mitochondrial DNA (mtDNA) deletion in most of the case. In this article, a case of KSS who has progressive external ophthalmoplegia (PEO), retinitis pigmentosa (RP), complete heart block, encephalopathy attacks, type-1 diabetes mellitus, ragged-red fiber (RRF) and lactic acidosis is presented and discussed in light of the literature available on this subjects. Diagnosis is confirmed by determination of mtDNA deletion.
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PMID:Kearns-Sayre syndrome. A case report. 967 32

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


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