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)

Friedreich's Ataxia (FA) is a neurologic disorder associated with a high prevalence of diabetes mellitus. To assess insulin secretion and insulin resistance, glucose and insulin responses to oral glucose and insulin binding to circulating monocytes and dextran gradient fractionated and unfractionated red blood cells (RBCs) were compared in 11 subjects with FA to 11 age-matched controls. Glucose and insulin responses were elevated from one to three hours after oral glucose in FA. The mean corrected insulin responses were not different while peripheral insulin activity (A) was significantly decreased (1.38 +/- 0.22 v 0.77 +/- 0.16, control v FA, P less than 0.025) indicating the presence of insulin resistance. A significant correlation between the degree of insulin resistance (A) and duration of neurologic symptoms was found (r = .65. P less than 0.025). Resistance to exogenous insulin was confirmed in ten subjects with FA by intravenous insulin tolerance tests (KITT, %/min, 6.25 +/- 0.90 v 3.93 +/- 0.61, P less than .05). Both FA and control groups showed highest insulin binding to fraction A (youngest) RBCs, but no difference was observed between the two groups. However, insulin binding to monocytes was significantly decreased in subjects with FA (% specific binding/10(7) cells/mL, 6.37 +/- 0.71 v 4.51 +/- 0.39, P less than 0.05, control v FA). This was associated with a decrease in apparent receptor affinity. We conclude that FA is associated with insulin resistance, which increases with the duration of neurologic impairment. The insulin binding to monocytes suggests that the insulin resistance may be partially explained by a receptor defect.
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PMID:Glucose intolerance in Friedreich's ataxia: association with insulin resistance and decreased insulin binding. 353 14

A 12 year old girl with Friedreich's ataxia, in whom progression from chemical to severe insulin-dependent diabetes mellitus occurred over a two year period, is presented. During the phase of subclinical diabetes her plasma immunoreactive insulin response to oral glucose was markedly increased, but when she became symptomatic gross insulin deficiency had supervened. This report draws attention to the unusual disorders of carbohydrate metabolism and insulin secretion that may occur in a variety of neurological conditions.
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PMID:Evolution of diabetes mellitus in a case of Friedreich's ataxia. 471 11

Nine patients with typical Friedreich's ataxia had normal levels of pyruvate and lactate in blood, urine, and CSF. Glucose, pyruvate, and lactate levels were also within the reference ranges after oral glucose loading. After intravenous pyruvate loading, the relative increase in blood pyruvate and lactate levels was significantly higher in Friedreich's ataxia patients than in controls. Significant differences between the two groups were also observed in lactate-pyruvate ratios at various times after infusion. The pyruvate loading test can be useful in demonstrating a defect in pyruvate metabolism in Friedreich's ataxia patients.
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PMID:Friedreich's ataxia: intravenous pyruvate load to demonstrate a defect in pyruvate metabolism. 649 99

Phase three of the Quebec Cooperative Study of Friedreich's Ataxia was devoted to an understanding of the physiopathology of individual symptoms on the basis of previously discovered biochemical leads. The present paper attempts to pull these results together by presenting, as a hypothesis, a unifying scheme of possible interactions and relationships. The central core of this hypothesis is the demonstration in Friedreich's ataxia of a state of mitochondrial energy deprivation. This is indirectly responsible for such associated and important symptoms as muscle weakness, dying-back neuropathy, scoliosis and hypertrophic cardiomyopathy. Secondarily, and possibly as an independent but linked-event, the entry of glucose into cells and pyruvate oxidation, are slowed down, favoring the development of diabetes. As a consequence, tissue concentrations of glutamic acid and aspartic acid are decreased, particularly in more vulnerable areas such as the cerebellum, brain stem and dorsal root ganglia. This tissue deficiency in putative excitatory neurotransmitters is directly responsible for the symptom of ataxia. This conclusion is reinforced by the correction of the ataxia in experimental animals, by the intraventricular injection of the same amino acids, and not by the injection of other stimulants of motricity. The observed mitochondrial energy deprivation could be the metabolic consequence of major changes in the linoleic acid (18.2) composition of inner mitochondrial membrane phospholipids, such as cardiolipin. Such decreases in membrane 18:2 could be the result of interference with the normal incorporation of this fatty acid to lipoproteins and/or cell membranes. It is at this level that the search for the specific enzyme defect in Friedreich's ataxia is continuing.
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PMID:Friedreich's ataxia 1980. An overview of the physiopathology. 678 90

Oral glucose tolerance, thyroid function tests, as well as thyrotropin, prolactin and growth hormone release after administration of thyrotropin releasing hormone, were evaluated in patients with Friedreich's ataxia and unaffected family members. Impaired glucose tolerance was found in the majority of family members, affected or not. Thyroid hormone levels and PRL and TSH responses to TRH, were similar in all and normal. However, GH responses to TRH were abnormal in half of the patients, but in none of the unaffected family members. Paradoxical responses to neuropeptides may characterize some Friedreich's ataxia patients, and may predict the possibility of therapeutic maneuvers with such peptides in these patients.
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PMID:Pituitary responses to a neuroactive tripeptide (TRH) in Friedreich's ataxia families. 680 4

This study extends previous observations of pyruvate metabolism in the spino-cerebellar degenerations by screening for abnormalities of pyruvate oxidation using the rise in blood pyruvate after an oral glucose load and examining the activity of the lipoamide dehydrogenase (LAD) moeity of the pyruvate dehydrogenase complex in the serum of 31 patients with Friedreich's ataxia, hereditary spastic ataxia and primary cerebellar degeneration. Serum LAD activity was significantly reduced in 10 Friedreich's ataxia patients when compared to controls and to 10 patients with spastic ataxia, thus confirming previous studies. Two patients with Friedreich's ataxia and 2 with primary cerebellar degeneration had abnormal blood pyruvate curves after oral glucose loading. The findings suggest that abnormal pyruvate oxidation occurs in some cases of Friedreich's ataxia and primary cerebellar degeneration and that the abnormality of pyruvate metabolism is not necessarily reflected in the serum LAD activity of these patients. The relevance of these findings to the heterogeneity of the hereditary ataxias is discussed.
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PMID:An investigation of pyruvate metabolism in patients with cerebellar and spinocerebellar degeneration. 689 66

Glucose tolerance and insulin release were evaluated in 16 families with Friedrich's ataxia. Impaired glucose tolerance differed in incidence according to the method of evaluation, but was increased in number in parents and siblings of Friedreich's cases. Insulin output was not quantitatively different from normal, although the insulin peak was often delayed. This finding, in association with impaired glucose tolerance, suggest a defect in glucose entry into cells.
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PMID:Friedreich's ataxia and oral glucose tolerance: I. The effect of ingested glucose on serum glucose and insulin values in homozygotes, obligate heterozygotes and potential carriers of the Friedreich's ataxia gene. 701 24

A series of biochemical tests aimed at elucidating the fundamental cause has been applied to 20 patients with Friedreich's ataxia. Special emphasis was placed upon pyruvate metabolism. The results demonstrate no precisely identifiable defect in the metabolism of pyruvate but indicate an abnormality in glucose uptake and metabolism.
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PMID:Biochemical and clinical studies of Friedreich's ataxia. 702 36

Homozygotes, obligatory heterozygotes and potential carriers of the Friedreich's Ataxia gene were tested with an oral glucose tolerance in order to assess a. the prevalence of abnormalities in glucose handling, b. the secretory pattern of two "diabetogenic" hormones, growth hormones and prolactin and c. to evaluate the possibility for detection of an abnormal trend in these hormones to be used as a genetic marker. Despite the high prevalence of glucose abnormalities horizontally and vertically in these families, the basal output and responses of these metabolic hormones to a glucose challenge were appropriate and thus not characteristic of any of the above groups.
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PMID:Friedreich's ataxia and oral glucose tolerance: II. The effect of ingested glucose on serum growth hormone in homozygotes, obligate heterozygotes and potential carriers of the Friedreich's ataxia gene. 721 54

Clinical characteristics of ten patients with Friedreich's disease are presented. Two cases were members of the same family, another patient had a brother with the disease, and in two cases there was consanguinity. The dominant inheritance pattern was absent in all cases. Initial symptoms and clinical signs were present under 5 years of age in six cases, and in three of them under 2 years of age. As reported in other series, in our cases the disorder first appeared in the legs. Other early manifestations included skeletal deformities and dysarthria, as well as diplopia, paresthesias and dizziness. Friedreich's ataxia results from pyramidal tract degeneration and changes in the cerebellum. Babinski sign was present in nine patients. Other findings were: muscular weakness, distal amyotrophy and distal dystonia. Two patients suffered epileptic attacks with typical EEG pattern. Kyphoscoliosis and pes cavum were constant skeletal deformities. ECG revealed signs of myocardial ischemis in nine patients, although none of them had symptomatology of heart disease. Glucose tolerance test carried out in three cases showed diabetic curves. Results of nerve speed conduction were as follows: normal in one case; decreased sensitive speed conduction in four cases, and decrease of both sensitive and motor speed conduction in other four cases. EMG showed signs of chronic denervation in three cases. These results coincide with those published by other authors.
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PMID:[Friedreich's disease. Clinical study of ten cases (author's transl)]. 737 33


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