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)

We studied 22 subjects carrying the A3243G point mutation of human mitochondrial DNA (mtDNA). In 14 cases the clinical phenotype was characterized by mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), while 8 patients had chronic progressive external ophthalmoplegia (CPEO). The proportion of A3243G heteroplasmy in muscle was determined by two methods; densitometry on a diagnostic restriction-fragment length polymorphism and solid-phase mini-sequencing. We found a highly significant inverse correlation between the percentage of A3243G mutation and the specific activity of complex I, the respiratory complex with the highest number of mtDNA-encoded subunits, suggesting a direct effect of the mutation on mtDNA translation. No correlation was observed between the percentage of mutated mtDNA and the presence or absence of specific clinical features, such as stroke, ophthalmoplegia and diabetes mellitus. However, in the MELAS group the percentage of mutated mtDNA molecules was strongly correlated with the age of onset, while no such correlation was found in the CPEO group, suggesting a different time-dependent evolution of the mutation in the two groups. Finally, in contrast with other mtDNA mutations associated with ragged-red fibres (RRF), in both MELAS3243 and CPEO3243 we observed a high proportion of RRF that were positive to the histochemical reaction to cytochrome c oxidase, a morphological feature that seems to be specific for the neuromuscular phenotypes associated with mutations affecting the tRNA(Leu(UUR)) gene.
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PMID:Genotype to phenotype correlations in mitochondrial encephalomyopathies associated with the A3243G mutation of mitochondrial DNA. 764 39

The investigation of pathogenic mitochondrial DNA (mtDNA) mutations has revealed a complex relation between patient genotype and phenotype. For unknown reasons, some mtDNA mutations produce specific clinical manifestations such as chronic progressive external ophthalmoplegia; myoclonic epilepsy and ragged-red fiber disease (MERRF); and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). To enhance our understanding of the association between genotype and phenotype, we investigated a patient with mitochondrial encephalomyopathy and severe cerebral calcifications for a mtDNA mutation. There was a deletion of one of three T:A nucleotide pairs in the tRNALeu(UUR) gene of the mtDNA involving positions 3271 to 3273. Pedigree analysis suggested that this mutation may have occurred spontaneously in the proband. This analysis represents the smallest mtDNA deletion observed to date and is the first deletion identified within a mitochondrial tRNA. This observation emphasizes the importance of delineating the precise mutation responsible for an oxidative phosphorylation disease for patient diagnosis as well as for genetic counseling of maternal lineage relatives.
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PMID:Mitochondrial encephalomyopathy associated with a single nucleotide pair deletion in the mitochondrial tRNALeu(UUR) gene. 785 27

A single mtDNA point mutation at nt 3243 has been associated with two different clinical phenotypes: mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes ('MELAS3243') and progressive external ophthalmoplegia ('PEO3243'). It has been shown that there is a much higher proportion of ragged-red fibers (RRF) with cytochrome c oxidase (COX) deficiency in PEO3243 than in MELAS3243. Using PCR/RFLP analysis of isolated individual skeletal muscle fibers from patients with both syndromes, we found a direct correlation between the localized concentration of the nt 3243 mutation and impairment of COX function at the single muscle fiber level: we found relatively low levels of mutant mtDNAs (56 +/- 21%) in 'normal' fibers; high levels (90 +/- 6%) in COX-positive RRF; and an almost complete segregation of mutant mtDNAs (95 +/- 3%) in COX-negative RRF. Thus, the differential distribution of fibers with extremely high concentrations of mutant mtDNAs characterizes, and probably distinguishes, the skeletal muscle of PEO and MELAS patients harboring the same nt-3243 mutation.
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PMID:Extremely high levels of mutant mtDNAs co-localize with cytochrome c oxidase-negative ragged-red fibers in patients harboring a point mutation at nt 3243. 791 29

This report describes a patient with mitochondrial encephalomyopathy who underwent an ophthalmic surgery under original neuroleptanesthesia. This 28-year-old female patient had been suffering from bilateral external ophthalmoplegia and blepharoptosis. Her preoperative neurological examination revealed a mitochondrial encephalomyopathy. Biopsy and blepharo-elevation for her left eyelid were scheduled. Anesthesia was induced with thiopental 5 mg.kg-1 and vecuronium 0.07 mg.kg-1, and maintained with total doses of 10 mg of droperidol, 400 micrograms of fentanyl and 4 mg of vecuronium. The patient recovered from anesthesia smoothly and her postoperative course was uneventful. Anesthetic management of patients with this disease and possible complications were discussed.
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PMID:[Neuroleptanesthesia for a patient with mitochondrial encephalomyopathy]. 793 72

We report a patient with mitochondrial encephalomyopathy presenting parkinsonism, as well as her brother who had ataxia but not parkinsonism. Both patients had myopathy, deafness, and insulin-dependent diabetes mellitus. The proband was a 55-year-old woman, who has developed progressive difficulty in walking and slowness of movement since 53 years of age, becoming bed-ridden at 55. Neurological examination revealed mental impairment, a masked face, Myerson's sign, vertical supranuclear ophthalmoplegia, and severe sensorineural deafness, hypokinesia, rigidospasticity, and weakness of the extremities. But tremor and cerebellar ataxia were absent. Her 48-year-old brother gradually developed weakness of the lower extremities and drunken gait over a few years. On neurologic examination, vertical supranuclear ophthalmoplegia, moderate sensorineural deafness, and cerebellar ataxia were present, but parkinsonism was absent. Three other siblings were reported to have died in early childhood. Cranial MR imaging showed cerebral atrophy and mild atrophy of the cerebellar vermis as well as mild periventricular hyperintensities in T2-weighted images in both patients. However, no infarcts were seen. Laboratory investigations revealed slightly elevated lactate and pyruvate levels in the proband and elevation of pyruvate in her brother. A biopsy specimen obtained from the quadriceps muscle showed ragged-red fibers with modified Gomori trichrome staining, and a decrease of complex I+III and complex II+III activity in the proband. Mitochondrial DNA (mtDNA) analysis using the polymerase chain reaction and restriction enzyme Apa I showed a point mutation in the tRNA(Leu)(UUR)) gene (an A to G transition at nucleotide 3243) in both patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Mitochondrial encephalomyopathy associated with parkinsonism and a point mutation in the mitochondrial tRNA(Leu)(UUR)) gene]. 802 31

We have investigated nine children with infantile onset of mitochondrial myopathy and two adults with myoclonus epilepsy and ragged-red fibers (MERRF) and chronic progressive external ophthalmoplegia (CPEO), respectively. These patients lacked any of the previously known pathogenic tRNA mutations. Southern blot analysis of muscle mtDNA revealed no deletions. The tRNA genes of muscle mtDNA were sequenced. Restriction enzyme analysis of PCR fragments was performed to verify the presence of the mutations identified by automatic sequencing. Several tRNA mutations were found, but they were all homoplasmic. Furthermore, the mutations were either present in controls or did not change nucleotides conserved between species. This strongly suggests that none of the tRNA mutations identified in the 11 patients with mitochondrial encephalomyopathy was pathogenic. It can thus be concluded that mitochondrial tRNA mutations and mtDNA deletions probably are an infrequent cause of mitochondrial disorders in infants. Patients with MERRF and CPEO may lack both pathogenic point mutations of tRNA genes and deletions of mtDNA.
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PMID:Automatic sequencing of mitochondrial tRNA genes in patients with mitochondrial encephalomyopathy. 815 39

The levels of mitochondrial electron transport system proteins cytochrome c oxidase (COX) and complex III were measured in muscle fibers of patients with mitochondrial encephalomyopathy using quantitative immunoelectron microscopy. In a patient with Leigh's encephalopathy, immunoreactive COX protein was decreased to 20% of the normal mean value in all muscle fibers examined, while the amount of complex III was within the normal range. In a patient with fatal infantile COX deficiency, the level of COX protein was found to be decreased to 27-40% of the normal value in all muscle fibers examined. In patients with mitochondrial myopathy, encephalopathy, lactic acidosis associated with stroke-like episodes (MELAS) and chronic progressive external ophthalmoplegia (CPEO), COX protein levels were decreased to 20% of normal in muscle fibers lacking COX activity. In normal fibers, however, COX protein levels were also normal. The amount of complex III protein was normal in COX-deficient muscle fibers. In two patients, in situ hybridization was performed for detection of mitochondrial mRNA. Mitochondrial mRNAs were found to be abundant in muscle fibers with decreased COX protein, suggesting a defect at the mitochondrial protein-synthesis level in a COX-deficient muscle fiber.
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PMID:Quantitative evaluation of electron transport system proteins in mitochondrial encephalomyopathy. 838 96

We report a 46-year-old female who presented progressive ophthalmoplegia and limb weakness. She was well until the age of 15 years when there was an onset of bilateral deafness. She became completely deaf by 20 years of age. She noted an onset of weakness in her legs when she was 27-years-old and of ptosis at 34 years of age. She was admitted to our hospital when she was 41-years-old. Neurological examination revealed near total ophthalmoplegia, bilateral ptosis, dysphagia, generalized muscle atrophy and weakness of approximately 4/5 degree, facial grimacing, athetotic movements in four limbs. Laboratory examinations revealed increase in blood lactate and pyruvate levels and diffuse low density change in the cerebral white matter in CT scans. She was thought to have a mitochondrial encephalomyopathy. She was discharged for follow-up, but her clinical course was that of a relentless deterioration. She was readmitted to our service in December 1989. She showed further progress in her weakness and muscle atrophy. Otherwise neurological examination was essentially similar to the previous one. Her cranial CT scans showed low density changes in striatum, thalamus and midbrain in addition to the white matter. Enzyme activities of the electron transport complexes revealed a moderate decrease in the succinatecytochrome c reductase activity, and the Southern blot analysis of mtDNA revealed multiple deletions in mitochondrial genomes. Two months after her admission, she developed bronchopneumonia, and expired on March 13th, 1990. Post-mortem examination revealed diffuse pallor of myeline in the cerebral white matter in K-B staining. A marked neuronal loss and gliosis were observed in putamen bilaterally. Skeletal muscles showed typical changes of mitochondrial myopathies with ragged-red fibers in Gomori-Trichrome staining, and crystalline inclusion bodies by electron microscopic observations. Some neurogenic atrophies were also seen. Oculomotor nuclei appeared intact. It was thought that she had an incomplete form of Kearns-Sayre syndrome. The patient was discussed in a neurological CPC of the departments of Neurology and Pathology of Juntendo University School of Medicine.
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PMID:[Forty-six-year-old woman with progressive external ophthalmoplegia and limb weakness]. 847 58

A 32-year-old woman developed chronic progressive hearing impairment, trunkal ataxia, bilateral ptosis and external ophthalmoplegia. She also showed slowly progressive mild to moderate proximal dominant muscle weakness and atrophy. ECG showed incomplete right bundle branch block. An aerobic exercise test showed abnormal blood lactate elevation and muscle biopsy revealed ragged-red fibers in addition to the myopathic change. Analysis of mitochondrial DNA extracted from biopsied muscle and fibroblast samples revealed a 1,758bp deletion from the cytochrome b to ND6 coding regions. Common mutations in tRNALeu(UUR) coding region to the mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) were not present. She was diagnosed as having incomplete Kearns-Sayre syndrome (KSS). Since the age of 35, she developed complex partial seizure attacks with secondary generalization frequently and at the age of 42, she had a severe generalized seizure with delayed consciousness loss followed by left hemiplegia. MRI showed wide T2-high signal lesions in the right temporo-parieto-occipital area. The proton MR-spectroscopy showed prominent increase of lactate beyond the lesions detected by MRI, indicating diffuse aerobic metabolic dysfunction in the central nervous system. We reviewed two other KSS cases with a stroke like episode, who also had epilepsy and large deletion but no tRNALeu(UUR) mutation, in mitochondrial DNA. Patients with KSS who have seizure may develop the stroke-like episode as seen in MELAS patients.
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PMID:[A case of incomplete Kearns-Sayre syndrome with a stroke like episode]. 940 43

Mitochondrial diseases are characterized by considerable clinical variability and are most often caused by mutations in mtDNA. Because of the phenotypic variability, epidemiological studies of the frequency of these disorders have been difficult to perform. We studied the prevalence of the mtDNA mutation at nucleotide 3243 in an adult population of 245,201 individuals. This mutation is the most common molecular etiology of MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes), one of the clinical entities among the mitochondrial disorders. Patients with diabetes mellitus, sensorineural hearing impairment, epilepsy, occipital brain infarct, ophthalmoplegia, cerebral white-matter disease, basal-ganglia calcifications, hypertrophic cardiomyopathy, or ataxia were ascertained on the basis of defined clinical criteria and family-history data. A total of 615 patients were identified, and 480 samples were examined for the mutation. The mutation was found in 11 pedigrees, and its frequency was calculated to be >=16. 3/100,000 in the adult population (95% confidence interval 11.3-21. 4/100,000). The mutation had arisen in the population at least nine times, as determined by mtDNA haplotyping. Clinical evaluation of the probands revealed a syndrome that most frequently consisted of hearing impairment, cognitive decline, and short stature. The high prevalence of the common MELAS mutation in the adult population suggests that mitochondrial disorders constitute one of the largest diagnostic categories of neurogenetic diseases.
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PMID:Epidemiology of A3243G, the mutation for mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes: prevalence of the mutation in an adult population. 968 91


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