Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A female infant was seen at the age of 2 months because of hypotonia, delayed motor development, and lactic acidosis, and she died at age 13 months due to respiratory failure. In a muscle specimen taken at 11 months and in a liver specimen obtained 1.5 hours postmortem, we found decreased activities of cytochrome c oxidase and long-chain acyl coenzyme A dehydrogenase. Neuropathological changes were typical for Leigh's subacute necrotizing encephalomyelopathy. To our knowledge, this is the first report of a combined defect of complex IV of the respiratory chain and of the long-chain specific acyl coenzyme A dehydrogenase of beta-oxidation in muscle and liver.
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PMID:Cytochrome c oxidase deficiency and long-chain acyl coenzyme A dehydrogenase deficiency with Leigh's subacute necrotizing encephalomyelopathy. 131 9

Three children displaying hypotonia, cardiac involvement and defects of the mitochondrial respiratory chain complexes are reported. The first case showed severe neonatal hypotonia, failure to thrive, hepatomegaly, dilation of the right cardiac cavities, profound lactic acidosis and amino aciduria. The boy died at the age of 7 weeks. In the second case hypotonia, severe cardiomyopathy, cyclic neutropenia, lactic acidosis and 3-methylglutaconic aciduria occurred. The boy died at the age of 27 months. The third case presented at the age of 16 months as an acute hypokinetic hypertrophic cardiomyopathy with transient hypotonia and mild lactic acidosis. Spontaneous clinical remission occurred. In all cases muscle biopsy was performed. Morphological studies failed to show ragged-red fibers but there was lipid storage myopathy and decreased cytochrome c oxidase activity. Biochemical studies confirmed the cytochrome c oxidase deficiency in muscle in all cases. It was associated with complex I III deficiency in case 1 and with severe deficits of all respiratory chain complexes in case 2. Post-mortem studies in case 1 indicated that complex IV was reduced in the liver but not in the heart and quantitative analysis of mtDNA revealed a depletion in muscle. Cases 1 and 2 shared some clinical features with fatal infantile myopathy associated with cytochrome c oxidase deficiency, while case 3 displayed a very unusual clinical presentation. The histochemical enzyme reaction of cytochrome c oxidase is useful for the diagnosis of mitochondrial myopathy because ragged-red fibers may be lacking. Finally, biochemical measurement of the different mitochondrial respiratory chain complexes is required because multiple defects are frequent and occasionally related to mtDNA depletion.
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PMID:Defects of the mitochondrial respiratory chain complexes in three pediatric cases with hypotonia and cardiac involvement. 132 Jun 61

A female child suffering from intrauterine growth retardation was born by caesarean section at 32 weeks. In the immediate newborn period there was a metabolic acidosis but this resolved. Hypotonia, muscular weakness and poor respiratory effort were evident and the child died at 6 days of age. A previous male sibling had died at 3 months of age after similar symptoms with seizures and a dysmyelination disorder. Post-mortem examination of both children showed damage to the basal ganglia. Defects in the activities of the pyruvate dehydrogenase complex, cytochrome oxidase and succinate cytochrome c reductase were found in cultured skin fibroblasts. Similar defects were found in isolated muscle mitochondria but not in isolated liver mitochondria from the patient. Immunoblotting for cytochrome oxidase showed that the multienzyme complex was not assembled in muscle and skin fibroblast mitochondria, but was assembled in liver mitochondria. Similar results were obtained in cultured skin fibroblast mitochondria for complex I of the mitochondrial respiratory chain. This is the first occasion that multiple defects have been demonstrated both in tissue and in culture skin fibroblasts in mitochondrial respiratory chain complexes.
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PMID:Fatal combined defects in mitochondrial multienzyme complexes in two siblings. 132 97

Fourteen new cases of cytochrome oxidase (COX)-associated Leigh syndrome (LS) are combined with 20 reported cases to describe the clinical, laboratory, and radiological features of this devastating metabolic condition. Three clinical stages are identified. Most patients have normal neurological development during the first 8-12 months (stage I). Somatic complaints are common, including chronic diarrhea, recurrent vomiting, anorexia, and decelerating body and head growth. The second stage evolves during late infancy and early childhood when motor regression becomes evident. Eye signs, altered breathing patterns, pyramidal, extrapyramidal, and cerebellar signs emerge and sudden clinical deterioration occurs during intercurrent infectious or metabolic stress. The last stage may extend from 2 to 10 years and is manifested by extreme hypotonia, swallowing difficulties and undernutrition. Feeding assistance is necessary and seizures may occur. The CSF lactate concentration is consistently elevated and MRI abnormalities are seen in the subcortical structures. COX deficiency affects most tissues, but is not always generalized. For example, 3 patients with a cardiomyopathy had normal COX activity in cultured skin fibroblasts. Nearly normal amounts of cross-reacting material are present by ELISA and immunoblot analyses. Parental consanguinity has been found in several families, the hereditary pattern is recessive and males are affected more commonly (2:1). The biomolecular abnormality causing COX deficiency in LS is unknown, but the available evidence implicates a nuclear-encoded protein that affects the structure or the stability of the holoenzyme complex.
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PMID:Cytochrome c oxidase-associated Leigh syndrome: phenotypic features and pathogenetic speculations. 165 84

Two siblings with infantile lactic acidosis and mitochondrial myopathy are described. The first child, a girl, died at 5 months of age from severe lactic acidosis after about 3 weeks of progressive muscular hypotonia. The younger brother had congenital lactic acidosis but no other symptoms until 6 months of age when progressive muscle weakness appeared. Treatment with dichloroacetate lowered the serum lactic acid level but did not affect his clinical condition. At 13 months of age, cardiomyopathy was diagnosed and he died at the age of 29 months of circulatory failure. Both children had mitochondrial myopathy. Postmortem examination of the boy revealed marked morphologic changes of the mitochondria in both skeletal muscle and the myocardium; biochemical investigation of skeletal muscle mitochondria demonstrated deficiencies in both complex I (NADH ferricyanide reductase) and complex IV (cytochrome c oxidase). The disease in these siblings differs in several respects from previously reported patients with mitochondrial myopathy and cytochrome c oxidase deficiency.
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PMID:Mitochondrial myopathy and cardiomyopathy in siblings. 274 28

A female infant presented with signs of general muscle hypotonia and increasing hypertrophy of the heart muscle. There was a constant lactic acidosis worsened after glucose intake. Serum lactate levels were increased up to 6.7 mmol/l. Serum alanine levels reached maximum concentrations of 2,800 mumol/l. The patient died after sudden cardiac arrest at 22 months of age. Histology of the heart showed the pattern of foamy myocardial transformation with accumulation of mitochondria and an increased glycogen content. Biochemical analysis of the skeletal muscle and the heart demonstrated signs of a disturbed respiratory chain. The content of cytochrome aa3 protein was decreased in skeletal muscle and heart mitochondria. It is suggested that respiratory chain defects may be the cause of foamy myocardial transformation of the heart.
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PMID:Foamy myocardial transformation in a child with a disturbed respiratory chain. 282 64

A 16 year old girl showed delayed psychomotor development. In infancy, exercise intolerance, cerebellar signs, deteriorated with increasing intercurrent infections, and disturbances of breathing and cardiac rhythm became manifest. From the age of 7 years there was chronic progressive psychomotor deterioration, with hypotonia, a bilateral pyramidal and cerebellar syndrome, and mild epilepsy. CSF pyruvate and lactate levels were elevated, and lactate content was elevated in the urine. There was an abnormally high rise of lactate levels on moderate exercise and an abnormal response to pyruvate loading. Quadriceps muscle biopsies obtained at age 10 and 16 years showed ragged-red fibres, and a decreased cytochrome c oxidase activity and cytochrome aa3 content. Cytochrome c oxidase activity in fibroblasts was normal. Clinical signs and symptoms in association with a disturbance of mitochondrial energy metabolism led us to diagnosis of probable Leigh syndrome.
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PMID:A mitochondrial encephalomyopathy with a partial cytochrome c oxidase deficiency of muscle. 284 25

A 2-month-old boy had progressive generalized weakness, hypotonia, and respiratory insufficiency requiring assisted ventilation. At age 3 1/2 months, he started having seizures and recurrent pulmonary infections; he died at age 7 months. Serum lactate was chronically elevated, but there was no aminoaciduria. Histochemical and ultrastructural studies of muscle biopsies at ages 2 and 3 months showed excessive mitochondria, lipid, and glycogen; a third biopsy at 6 months showed marked increase in perimysial fibrous and fat tissue. Cytochrome c oxidase activity was 7% of normal in the first biopsy and undetectable in the others. Cytochrome spectra of mitochondria isolated from postmortem muscle showed complete lack of cytochrome aa3. Antibodies were obtained against cytochrome c oxidase purified from normal human heart. Immunotitration and enzyme-linked immunosorbent assay (ELISA) showed decreased immunologically reactive enzyme protein in the patient's muscle, but SDS-PAGE electrophoresis of immunoprecipitates of muscle mitochondrial extracts showed the presence of all cytochrome c oxidase subunits. These data suggest that decreased synthesis of one or more subunits may result in markedly decreased concentration of electrophoretically normal complex IV in skeletal muscle.
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PMID:Fatal infantile cytochrome c oxidase deficiency: decrease of immunologically detectable enzyme in muscle. 298 57

A 3-day-old girl had a syndrome of lethargy and lactic acidosis. Pregnancy and delivery had been normal; there was no consanguinity or family history of neuromuscular disease. At age 4 1/2 months, she had generalized weakness, hypotonia, areflexia, and macroglossia. She developed cyanosis and respiratory failure, and marked cardiomegaly was noted. She died at age 8 1/2 months of cardiac arrest. Results from a muscle biopsy specimen obtained at age 4 1/2 months showed ragged-red fibers and increased glycogen and lipid droplets. With the cytochrome c oxidase reaction, only 5% of the fibers stained positively in the biopsy specimen. Cytochrome c oxidase activity was 7.3% of normal in muscle mitochondria and 12.2% of normal in heart mitochondria. Reduced-minus-oxidized cytochrome spectra showed lack of the cytochrome aa3 peak. Immunotitration using antibodies against purified human heart cytochrome c oxidase showed normal amount of cross-reacting material in both heart and muscle. The genetic error could have involved a cytochrome c oxidase isozyme common to heart and muscle.
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PMID:Myopathy and fatal cardiopathy due to cytochrome c oxidase deficiency. 302 95

Measurement of pyruvate and lactate produced from glucose by confluent skin fibroblast cultures from 95 patients with lactic acidemia revealed 10 in whom the lactate/pyruvate ratio (L/P) was increased (L/P = 57 to 232) compared with that observed in control cell lines (L/P = 18 to 35). Mitochondria prepared from these cells revealed two types of respiratory chain defect. In four patients the deficient activity was present in NADH-coenzyme Q reductase (14% to 21% of controls), and in six the deficiency was in cytochrome c oxidase (21% to 28% of controls). The four patients with NADH-coQ reductase deficiency presented early with lactic acidosis, respiratory failure, anorexia, and hypotonia; all four died within 7 months. The group with cytochrome oxidase deficiency had a somewhat later (18 months to 2 years of age) presentation with milder lactic acidemia, but also with hypotonia and anorexia. They had delayed development, beginning to walk and talk at 18 to 24 months, and then slowly regressed. Although an investigation of central nervous system disorders in this latter group has not been possible, the clinical progression fits into the broad category of Leigh disease. We conclude that in these two groups respiratory chain defects can be detected and localized by the use of skin fibroblast cultures.
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PMID:Clinical presentation of mitochondrial respiratory chain defects in NADH-coenzyme Q reductase and cytochrome oxidase: clues to pathogenesis of Leigh disease. 302 93


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