Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 48 year old woman with ataxia with vitamin E deficiency is described. Gene analysis identified two point mutations in exon 1 of the alpha-tocopherol transfer protein (alpha-TTP) gene, one missense mutation and an upstream initiation codon mutation in the 5'-untranslated region (Kozak sequence). The latter mutation is the first one identified in the translation regulatory region. This mutation decreased the level of alpha-TTP protein expression. The clinical features included uncommon urinary disturbance and deafness and relatively rare retinitis pigmentosa. Supplementary therapy increased her serum vitamin E concentration to the normal range with mild improvement of the deep senses.
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PMID:Ataxia caused by mutations in the alpha-tocopherol transfer protein gene. 1089 5

A case of ataxia with isolated vitamin E deficiency, in conjunction with supportive genetic studies, is reported. This is a neurodegenerative condition that involves a mutation in the tocopherol (alpha) transfer protein gene (TTPA). Measurement of serum vitamin E concentration should be included as part of the investigations in children with progressive ataxia, even in the absence of fat malabsorption. Early treatment with vitamin E may protect such patients against further neurological damage.
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PMID:Ataxia with isolated vitamin E deficiency: a clinical, biochemical and genetic diagnosis. 1103 14

Alpha-tocopherol transfer protein (alpha-TTP), a cytosolic protein that specifically binds alpha-tocopherol, is known as a product of the causative gene in patients with ataxia that is associated with vitamin E deficiency. Targeted disruption of the alpha-TTP gene revealed that alpha-tocopherol concentration in the circulation was regulated by alpha-TTP expression levels. Male alpha-TTP(-/-) mice were fertile; however, placentas of pregnant alpha-TTP(-/-) females were severely impaired with marked reduction of labyrinthine trophoblasts, and the embryos died at mid-gestation even when fertilized eggs of alpha-TTP(+/+) mice were transferred into alpha-TTP(-/-) recipients. The use of excess alpha-tocopherol or a synthetic antioxidant (BO-653) dietary supplement by alpha-TTP(-/-) females prevented placental failure and allowed full-term pregnancies. In alpha-TTP(+/+) animals, alpha-TTP gene expression was observed in the uterus, and its level transiently increased after implantation (4.5 days postcoitum). Our results suggest that oxidative stress in the labyrinth region of the placenta is protected by vitamin E during development and that in addition to the hepatic alpha-TTP, which governs plasma alpha-tocopherol level, the uterine alpha-TTP may also play an important role in supplying this vitamin.
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PMID:Alpha-tocopherol transfer protein is important for the normal development of placental labyrinthine trophoblasts in mice. 1107 32

To prevent neuronal damage, patients with ataxia with isolated vitamin E deficiency need lifelong supplementation with high doses of vitamin E. Short interruptions of therapy, such as occur in malcompliance, do not lead to clinical symptoms. However, the authors show that even short withdrawals may cause a prolonged decrease of the total radical trapping capacity of plasma; its major contributors, such as urate and sulfhydryl groups, fail to compensate for the missing vitamin E.
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PMID:Ataxia with vitamin E deficiency: biochemical effects of malcompliance with vitamin E therapy. 1109 24

In this chapter; we have described the role of nutritional supplements or selective dietary restriction (or both) on the maintenance and function of the retina and nervous system in some diseases. Oral vitamin A therapy has proven to be effective in the treatment of the common forms of retinitis pigmentosa. Bassen-Kornzweig disease can be treated with vitamin A and vitamin E and, in some cases, with vitamin K. Vitamin E therapy for Friedreich-like ataxia associated with retinitis pigmentosa has been shown to be effective in the short term. Classic Refsum's disease responds to a low phytol-low phytanic acid diet. Undoubtedly, future research will bring more insight into the biochemical pathways responsible for other diseases and, it is hoped, aid in developing treatments for additional retinal degenerations associated with systemic neurological disease.
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PMID:Treatable forms of retinitis pigmentosa associated with systemic neurological disorders. 1119 37

Friedreich's ataxia (FA) is the most common form of autosomal recessive spinocerebellar ataxia and is often associated with a cardiomyopathy. The disease is caused by an expanded intronic GAA repeat, which results in deficiency of a mitochondrial protein called frataxin. In the yeast YFH1 knockout model of the disease there is evidence that frataxin deficiency leads to a severe defect of mitochondrial respiration, intramitochondrial iron accumulation, and associated production of oxygen free radicals. Recently, the analysis of FA cardiac and skeletal muscle samples and in vivo phosphorus magnetic resonance spectroscopy (31P-MRS) has confirmed the deficits of respiratory chain complexes in these tissues. The role of oxidative stress in FA is further supported by the accumulation of iron and decreased aconitase activities in cardiac muscle. We used 31P-MRS to evaluate the effect of 6 months of antioxidant treatment (Coenzyme Q10 400 mg/day, vitamin E 2,100 IU/day) on cardiac and calf muscle energy metabolism in 10 FA patients. After only 3 months of treatment, the cardiac phosphocreatine to ATP ratio showed a mean relative increase to 178% (p = 0.03) and the maximum rate of skeletal muscle mitochondrial ATP production increased to 139% (p = 0.01) of their respective baseline values in the FA patients. These improvements, greater in prehypertrophic hearts and in the muscle of patients with longer GAA repeats, were sustained after 6 months of therapy. The neurological and echocardiographic evaluations did not show any consistent benefits of the therapy after 6 months. This study demonstrates partial reversal of a surrogate biochemical marker in FA with antioxidant therapy and supports the evaluation of such therapy as a disease-modifying strategy in this neurodegenerative disorder.
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PMID:Antioxidant treatment improves in vivo cardiac and skeletal muscle bioenergetics in patients with Friedreich's ataxia. 1135 49

Ataxia with vitamin E (Vit E) defciency (AVED) is an autosomal recessive disorder caused by mutations of the alpha tocopherol transfer protein gene. The Friedreich ataxia phenotype is the most frequent clinical presentation. In AVED patients, serum Vit E levels are very low in the absence of intestinal malabsorption. As Vit E is a major antioxidant agent, Vit E deficiency is supposed to be responsible for the pathological process. Twenty-four AVED patients were fully investigated (electromyography, nerve conduction velocity (NVC) studies, somatosensory evoked potentials, cerebral computed tomography scan, sural nerve biopsy, genetic studies) and supplemented with Vit E (800 mg daily) during a 1-year period. Clinical evaluation was mainly based on the Ataxia Rating Scale (ARS) for cerebellar ataxia assessment and serum Vit E levels were monitored. Serum Vit E levels normalized and ARS scores decreased moderately but significantly suggesting clinical improvement. Better results were noted with mean disease duration < or = 15 years. Reflexes remained abolished and posterior column disturbances unchanged. Vitamin E supplementation in AVED patients stabilizes the neurological signs and can lead to mild improvement of cerebellar ataxia, especially in early stages of the disease.
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PMID:Effect of vitamin E supplementation in patients with ataxia with vitamin E deficiency. 1155 13

alpha-Tocopherol transfer protein (alpha-TTP) maintains the concentration of serum alpha-tocopherol (vitamin E), one of the most potent fat-soluble antioxidants, by facilitating alpha-tocopherol export from the liver. Mutations of the alpha-TTP gene are linked to ataxia with isolated vitamin E deficiency (AVED). We produced a model mouse of AVED by deleting the alpha-TTP gene, which showed ataxia and retinal degeneration after 1 year of age. Because the brain alpha-TTP functions in maintaining alpha-tocopherol levels in the brain, alpha-tocopherol was completely depleted in the alpha-TTP(-/-) mouse brain, and the neurological phenotype of alpha-TTP(-/-) mice is much more severe than that of wild-type mice when maintained on an alpha-tocopherol-deficient diet. Lipid peroxidation in alpha-TTP(-/-) mice brains showed a significant increase, especially in degenerating neurons. alpha-Tocopherol supplementation suppressed lipid peroxidation and almost completely prevented the development of neurological symptoms. This therapy almost completely corrects the abnormalities in a mouse model of human neurodegenerative disease. Moreover, alpha-TTP(-/-) mice may prove to be excellent animal models of delayed onset, slowly progressive neuronal degeneration caused by chronic oxidative stress.
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PMID:Delayed-onset ataxia in mice lacking alpha -tocopherol transfer protein: model for neuronal degeneration caused by chronic oxidative stress. 1175 62

We report a 61-year-old man with vitamin E deficiency, presenting with, myopathy as an only clinical symptom. In 1997, at 59 years of age, he noted mild proxymal-muscle weakness and atrophy in the four extremities, nine years after he received a Billroth II partial gastrectomy for a gastric ulcer. His muscle weakness slowly exacerbated, and he was admitted to our hospital in 1999. On admission, neurological examination confirmed mild proximal-muscle weakness and atrophy in the four extremities. Intelligence, cranial nerves, coordination, sensation and tendon reflexes were all normal. Laboratory examination showed normochromic anemia (Hb 9.9 g/dl, Ht 30.9%, MCV 97.5 fl, MCHC 31.2 pg), hypoproteinemia (5.0 g/dl), and hypocholesterolemia (107 mg/dl). The levels of serum CK, lactate and pyruvate were normal. The serum vitamin E level was markedly reduced (0.17 mg/dl; normal 0.75-1.41). Cerebrospinal fluid was normal. Nerve conduction, sensory evoked potentials (SEP), electromyography (EMG), head CT and electroencephalography (EEG) were all normal. Muscle biopsy from the right deltoid muscle showed both mild myogenic and neurogenic changes. Remarkably, type 1 muscle fiber predominance and granular accumulation of autofluorescent lipofuscin granules in the muscle fibers were found. These pathological findings were compatible with those of vitamin E-deficient myopathy. Thus, he was diagnosed as having vitamin E-deficient myopathy, which was confirmed by apparent effective supplementation of vitamin E. Interestingly, our present case did not show any other neurological manifestations such as deep sensory disturbance, sensory ataxia or polyneuropathy. A long-term workload due to hard physical labor and smoking in our patient may have accelerated oxidative muscle damage, resulting in amyotrophy mainly due to vitamin E deficient myopathy.
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PMID:[A patient with vitamin E deficient, myopathy presenting with amyotrophy]. 1180 55

A number of ataxias have been shown to result from defects in mitochondrial function. The genes responsible for Friedreich ataxia (FRDA) and for X-linked sideroblastic anemia with ataxia are nuclear genes that encode mitochondrial proteins. These genes, which are highly conserved in species as diverse as humans and yeast, play a role in mitochondrial iron metabolism and in the formation of iron-sulfur clusters. Defects in vitamin E metabolism, due to mutations in tocopherol transfer protein (TTP), also result in ataxia. It is hypothesized that the biochemical feature common to these ataxias is increased oxidant damage either through increased oxidants or decreased anti-oxidants.
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PMID:Spinocerebellar ataxias due to mitochondrial defects. 1185 Jan 12


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