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 ataxia and ataxia with selective vitamin E deficiency (AVED) share very similar clinical phenotypes. We have mapped the AVED locus to proximal 8q with only three large consanguinous Tunisian families, representing to our knowledge the first use of homozygosity mapping for primary linkage analysis. Subsequently, three additional families showed linkage with the same markers. A maximum lod score of 17.9 was obtained at theta = 0 for the haplotype D8S260-D8S510, consisting of the two closest markers. With only 6 families, the AVED locus is therefore mapped precisely as illustrated by the lod-1 confidence interval of 2.4 cM on either side of D8S260-D8S510. Isolation of a yeast artificial chromosome contig > 800 kilobases (kb) showed that D8S260 and D8S510 are less than 400 kb apart.
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PMID:Localization of Friedreich ataxia phenotype with selective vitamin E deficiency to chromosome 8q by homozygosity mapping. 825 33

Familial vitamin E deficiency (AVED) causes ataxia and peripheral neuropathy that resembles Friedreich's ataxia. AVED is thought to be caused by a defect in the transport of vitamin E in liver cells, which is the probable function of alpha-tocopherol transfer protein (alphaTTP). We have cloned the cDNA and several genomic phage clones covering the entire human alphaTTP gene and determined the junctions between the five exons and four introns that composed the gene for human alphaTTP. Three mutations in three unrelated North American families with AVED were identified. Two mutations, 485delT and 513insTT, cause a frame shift and a premature stop codon and the third mutation 574G-->A would substitute Arg192 to His in alphaTTP. The 2 patients with a severe form of AVED were homozygous with 485delT and 513insTT, respectively, while the patient with a mild form of the disease was compound heterozygous with 513insTT and 574G-->A. These findings have identified the underlying genetic defect in AVED and have confirmed the role of alphaTTP in AVED.
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PMID:Human alpha-tocopherol transfer protein: gene structure and mutations in familial vitamin E deficiency. 860 47

Children deficient in vitamin E have various neurologic symptoms. 2 cases representing different mechanisms of this vitamin deficiency are reported. A 15-year-old boy with fat malabsorption due to cystic fibrosis who was diagnosed as being vitamin E deficient (< 0.5 mg/l), had typical neuropathies. On the other hand, a 12-year-old Beduin girl had isolated vitamin E deficiency, as well as neurological symptoms suggestive of Friedrich's ataxia. Vitamin E supplementation by intramuscular injection in the first case and per os in the second led to significant improvement in neurological symptoms.
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PMID:[Neurological symptoms associated with vitamin E deficiency]. 868 50

Friedreich's ataxia is the most common inherited spinocerebellar ataxia. A decade of linkage and physical mapping studies have culminated in the identification of the Friedreich's ataxia gene. The presence of homologues in purple bacterial genomes, but not in other bacteria, allows us to infer a mitochondrial location for frataxin (Friedreich's ataxia protein) on the basis of bacterial phylogeny. Frataxin possesses a non-globular N-terminus domain providing a candidate mitochondrial targeting peptide. Clues to the function of frataxin are provided by the mitochondrial location, a clinically similar ataxia with vitamin E deficiency, and certain neuropathies with mitochondrial DNA instability caused by mutations in nuclear genes.
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PMID:Friedreich's ataxia protein: phylogenetic evidence for mitochondrial dysfunction. 893 Dec 68

We describe 4 siblings of a consanguineous Bedouin family with Friedreich ataxia phenotype in whom low serum vitamin E levels without other indicators of fat malabsorption were detected. Although age of onset and some of the clinical features were alike in all 4 patients, the electrophysiological parameters were markedly abnormal in 2, but normal in the other 2. Erythrocytes revealed both membranous and intracellular evidence of oxidative damage. The mutations described in other families with ataxia with isolated vitamin E deficiency were not detectable, nor was an abnormal single-stranded conformation polymorphism pattern apparent in the three exons at the 3' region of the gene. Vitamin E administration in pharmacological doses improved the neurological condition in 2 patients and also corrected some of the patients' erythrocyte cell abnormalities. The finding of vitamin E deficiency in other cases of Friedreich ataxia phenotype may allow treatment at an early stage of the disease, when large dose Vitamin E therapy may reverse the neurological lesions.
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PMID:Ataxia with isolated vitamin E deficiency in four siblings. 897 36

The neuropathological findings in a Tunisian patient with Friedreich's ataxia with vitamin E deficiency are reported. The main histological changes are: (1) spinal sensory system demyelination with neuronal atrophy, axonal spheroids and corpora amylacea; (2) neuronal lipofuscin accumulation in the third cortical layer of the cerebral cortex, thalamus, lateral geniculate body, twelfth and ambiguus nuclei, spinal horns and posterior root ganglia. Ultrastructurally, the lipopigments were of uniform granularity without lipid droplets.
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PMID:Friedreich's ataxia with isolated vitamin E deficiency: a neuropathological study of a Tunisian patient. 919 4

Friedreich ataxia is a progressive neurodegenerative disorder caused by loss of function mutations in the frataxin gene. In order to unravel frataxin function we developed monoclonal antibodies raised against different regions of the protein. These antibodies detect a processed 18 kDa protein in various human and mouse tissues and cell lines that is severely reduced in Friedreich ataxia patients. By immunocytofluorescence and immunocytoelectron microscopy we show that frataxin is located in mitochondria, associated with the mitochondrial membranes and crests. Analysis of cellular localization of various truncated forms of frataxin expressed in cultured cells and evidence of removal of an N-terminal epitope during protein maturation demonstrated that the mitochondrial targetting sequence is encoded by the first 20 amino acids. Given the shared clinical features between Friedreich ataxia, vitamin E deficiency and some mitochondriopathies, our data suggest that a reduction in frataxin results in oxidative damage.
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PMID:Frataxin is reduced in Friedreich ataxia patients and is associated with mitochondrial membranes. 930 53

Friedreich ataxia (FA), the most frequent cause of recessive ataxia, is attributable, in most cases, to a large expansion of an intronic GAA repeat, resulting in decreased expression of the target frataxin gene. This gene encodes a novel mitochondrial protein that has homologues of unknown function in yeast and even in gram-negative bacteria. Yeast deficient in the frataxin homologue accumulate iron in their mitochondria and show increased sensitivity to oxidative stress. This finding suggests that FA patients suffer from a mitochondrial dysfunction that causes free-radical toxicity, reminiscent of the clinically similar ataxia caused by inherited isolated vitamin E deficiency.
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PMID:Deciphering the cause of Friedreich ataxia. 938 53

Ataxia with vitamin E deficiency (AVED), or familial isolated vitamin E deficiency, is a rare autosomal recessive neurodegenerative disease characterized clinically by symptoms with often striking resemblance to those of Friedreich ataxia. We recently have demonstrated that AVED is caused by mutations in the gene for alpha-tocopherol transfer protein (alpha-TTP). We now have identified a total of 13 mutations in 27 families. Four mutations were found in >=2 independent families: 744delA, which is the major mutation in North Africa, and 513insTT, 486delT, and R134X, in families of European origin. Compilation of the clinical records of 43 patients with documented mutation in the alpha-TTP gene revealed differences from Friedreich ataxia: cardiomyopathy was found in only 19% of cases, whereas head titubation was found in 28% of cases and dystonia in an additional 13%. This study represents the largest group of patients and mutations reported for this often misdiagnosed disease and points to the need for an early differential diagnosis with Friedreich ataxia, in order to initiate therapeutic and prophylactic vitamin E supplementation before irreversible damage develops.
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PMID:Ataxia with isolated vitamin E deficiency: heterogeneity of mutations and phenotypic variability in a large number of families. 946 7

Ataxia with vitamin E deficiency is an autosomal recessive condition associated with a defect in the a-tocopherol transfer protein. Clinically it manifests as a progressive ataxia with a phenotype resembling that of Friedreich's ataxia. There is some evidence that progression of neurological symptoms is prevented by vitamin E therapy. A patient is described who was given a clinical diagnosis of Friedreich's ataxia. Molecular genetic analysis showed the absence of the frataxin gene expansion. Subsequent vitamin E assay showed deficiency and a diagnosis of ataxia with vitamin E deficiency was made. It is recommended that all patients with ataxia of unknown cause should have vitamin E deficiency excluded. When a diagnosis of Friedreich's ataxia is considered patients should have frataxin analysis in addition. Further, neurologists should be aware that ataxia with vitamin E deficiency may present as "mutation negative" Friedreich's ataxia.
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PMID:Ataxia with isolated vitamin E deficiency presenting as mutation negative Friedreich's ataxia. 952 51


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