Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016719 (Friedreich's ataxia)
 2,098 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clinical, ultrastructural and biochemical studies are reported in a 42-year-old woman presenting with congenital pes cavus who, at the age of 23 years, developed slowly progressive distal amyotrophies, hypesthesia, bilateral hearing loss and severe cardiopathy leading to death. There were skeletal anomalies, mild reduction of motor NCVs, but no corneal opacity, retinitis pigmentosa, organomegaly or vacuolated lymphocytes. Autopsy disclosed severe thickening of fibrous tissues (endocardium, cerebrospinal dura) with accumulation of vacuolated cells containing glycosaminoglycans in numerous membrane-bound cytoplasmic vacuoles, and/or compound multilamellar or zebra-body-like structures. The CNS, in addition to enlarged perivascular lacunes in cerebral white matter with lipid-containing macrophages, showed neuronal lipid storage in thalamus, hypothalamus, hippocampus, brain stem nuclei, spinal motor neurons and Purkinje cell dendrites. Ultrastructurally, lamellated inclusions containing gangliosides were seen in mesenchymal cells, oligodendrocytes, pericytes and Schwann cells. Neurons contained abundant ceroid but no lamellated inclusions. Neurochemistry revealed decrease of alpha-L-iduronidase activity in brain tissue to 4% of normal, normal activities of other lysosomal enzymes, and normal lipid and ganglioside patterns. While the morphology and neurochemistry data are characteristic of mucopolysaccharidosis I, the phenotype of adult alpha-L-iduronidase deficiency mimicking Friedreich's disease has not been described so far.
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PMID:New phenotype of adult alpha-L-iduronidase deficiency (mucopolysaccharidosis I) masquerading as Friedreich's ataxia with cardiopathy. 212 5

Previous studies in our laboratory had demonstrated alterations in the physical state of membrane proteins in erythrocytes in Huntington's disease. In order to assess the specificity of our findings, the results of electron spin resonance studies of protein and lipid components, scanning electron-microscopic studies, enzymatic analyses of membrane-bound sodium plus potassium stimulated, magnesium-dependent adenosine triphosphatase and protein kinase, and cell deformability studies of erythrocyte membranes have been performed in the neurological disorders, Huntington's disease, Friedreich's ataxia, Alzheimer's disease, amyotrophic lateral sclerosis, and myotonic and Duchenne muscular dystrophy. Comparison of the results revealed that alterations in the biophysical and biochemical states of erythrocyte membranes in each disorder are specific to the particular disease state with the exception of those in Friedreich's ataxia and Alzheimer's disease. In the latter instance, the clinical and pathological alterations suggest that these two diseases have different primary defects. Our studies suggest that the molecular basis of each disease is different. In addition, the results suggest that biophysical and biochemical investigations of extraneural tissue in Huntington's disease and other neurological disordes have the potential of clarifying the molecular mechanisms by which these diseases arise.
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PMID:Specificity of biophysical and biochemical alterations in erythrocyte membranes in neurological disorders--Huntington's disease, Friedreich's ataxia, Alzheimer's disease, amyotrophic lateral sclerosis, and myotonic and duchenne muscular dystrophy. 625 Nov 75

NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria is a complicated, energy-transducing, membrane-bound enzyme that contains 45 different subunits, a non-covalently bound flavin mononucleotide, and eight iron-sulfur clusters. The mechanisms of NADH oxidation and intramolecular electron transfer by complex I are gradually being defined, but the mechanism linking ubiquinone reduction to proton translocation remains unknown. Studies of ubiquinone reduction by isolated complex I are problematic because the extremely hydrophobic natural substrate, ubiquinone-10, must be substituted with a relatively hydrophilic analogue (such as ubiquinone-1). Hydrophilic ubiquinones are reduced by an additional, non-energy-transducing pathway (which is insensitive to inhibitors such as rotenone and piericidin A). Here, we show that inhibitor-insensitive ubiquinone reduction occurs by a ping-pong type mechanism, catalyzed by the flavin mononucleotide cofactor in the active site for NADH oxidation. Moreover, semiquinones produced at the flavin site initiate redox cycling reactions with molecular oxygen, producing superoxide radicals and hydrogen peroxide. The ubiquinone reactant is regenerated, so the NADH:Q reaction becomes superstoichiometric. Idebenone, an artificial ubiquinone showing promise in the treatment of Friedreich's Ataxia, reacts at the flavin site. The factors which determine the balance of reactivity between the two sites of ubiquinone reduction (the energy-transducing site and the flavin site) and the implications for mechanistic studies of ubiquinone reduction by complex I are discussed. Finally, the possibility that the flavin site in complex I catalyzes redox cycling reactions with a wide range of compounds, some of which are important in pharmacology and toxicology, is discussed.
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PMID:Reduction of hydrophilic ubiquinones by the flavin in mitochondrial NADH:ubiquinone oxidoreductase (Complex I) and production of reactive oxygen species. 1922 2