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)

Neuronal voltage-gated calcium channels (VGCCs) are critical to numerous cellular functions including synaptogenesis and neurotransmitter release. Mutations in individual subunits of VGCCs are known to result in a wide array of neurological disorders including episodic ataxia, epilepsy, and migraines. The characterization of these disorders has focused on channel function within the brain. However, a defect in the retina-specific alpha1F subunit of an L-type VGCC results is a loss of visual sensitivity or the incomplete form of X-linked congenital stationary night blindness (CSNB2). Based on the electroretinographic phenotype of these patients this channel type is localized to the axon terminal of photoreceptor cells and results in a loss of signal transmission from photoreceptors to bipolar cells. A mouse with a deletion of the beta2 subunit of VGCCs in the central nervous system was recently shown to have a similar phenotype as CSNB2 patients. The identification of the role of VGCCs in this disorder highlights the potential association of other VGCC mutations with retinal disorders. The study of the role of these channels in normal retinal function may also be elucidated by the characterization of retinal structure and visual function in the numerous knockout, transgenic, and naturally occurring mouse mutants currently available.
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PMID:Using mutant mice to study the role of voltage-gated calcium channels in the retina. 1259 37

Mild subclinical impairment of neuromuscular transmission can be detected with single-fibre electromyography (SFEMG) in subgroups of patients suffering from migraine and could be due to dysfunctioning Ca2+-channels on motor axons controlling stimulation-induced acetylcholine release. Acetazolamide, which is thought to ameliorate ion channel function, was shown effective in familial hemiplegic migraine and episodic ataxia type 2, both of which are associated with mutations of the neuronal Ca2+-channel gene CACNA1A, as well as in aura status. We treated therefore in an open pilot study five non-hemiplegic migraineurs showing mild SFEMG abnormalities with acetazolamide for several weeks. This was followed by a normalization of SFEMG recordings in all patients and by clinical improvement in four. These results support the assumption that the subclinical impairment of neuromuscular transmission found in certain migraineurs might be due to dysfunctioning Ca2+-channels.
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PMID:Acetazolamide acts on neuromuscular transmission abnormalities found in some migraineurs. 1260 61

The antiphospholipid syndrome (APS, Hughes' syndrome), first described in 1983, is a prothrombotic disease in which neurological events feature prominently. Strokes, transient ischaemic attacks, and headaches (including migraine) are important complications. However, it is clear that other neurological symptoms, including diplopia, memory loss, ataxia, and "multiple sclerosis-like" features are common. A notable feature of Hughes' syndrome is the clinical response to anticoagulants; features such as headache and memory loss often improving dramatically with appropriate warfarin dosage. APS may well become recognised as an important (and potentially treatable) cause of neurological disease.
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PMID:Migraine, memory loss, and "multiple sclerosis ". Neurological features of the antiphospholipid (Hughes') syndrome. 1367 70

The paroxysmal dyskinesias (PxDs) are involuntary, intermittent movement disorders manifested by dystonia, chorea, athetosis, ballismus or any combination of these hyperkinetic disorders. Paroxysmal kinesigenic dyskinesia (PKD), one of the four main types of PxD, involves sudden attacks of dyskinesias induced by voluntary movements. PKD most commonly occurs sporadically or as an autosomal-dominant familial trait with variable penetrance. Many causes of secondary PKD are being recognized. The exact pathophysiology of the PxDs awaits further elucidation, although basal ganglia dysfunction appears to play a major role. Although the precise gene remains unknown, genetic linkage studies have isolated loci on chromosome 16, which colocalizes with the locus for familial infantile convulsions and paroxysmal choreoathetosis in some studies. The episodic nature of PKD and its relationship with other episodic diseases, such as epilepsy, migraine, and episodic ataxia, suggests channelopathy as a possible underlying etiology. PKD may remit spontaneously, but it also responds well to anticonvulsants as well as some other agents.
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PMID:Paroxysmal kinesigenic dyskinesias. 1278 50

Hashimoto's encephalopathy may present with a wide variety of different neurological symptoms and signs. These include recurrent severe migrainous headache, psychoses, seizures, ataxia, dementia, stupor and coma. We present a personal series of 18 adult patients with Hashimoto's encephalopathy and a review of the literature in this paper. The natural history, laboratory abnormalities and neuroimaging data in these cases favour an immunopathological basis for this syndrome similar to relapsing acute disseminated encephalomyelitis. We suggest that Hashimoto's encephalomyelitis should be considered in the differential diagnosis of seizures, coma, atypical migraine and reversible dementia. Serological screening for anti-thyroid antibody should form part of the initial investigations in all relapsing and reversible encephalopathies.
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PMID:The clinical spectrum, diagnosis, pathogenesis and treatment of Hashimoto's encephalopathy (recurrent acute disseminated encephalomyelitis). 1287 Oct 97

CoQ transfers electrons from complexes I and II of the mitochondrial respiratory chain to complex III. There are very few reports on human CoQ deficiency. The clinical presentation is usually characterized by: epilepsy, muscle weakness, ataxia, cerebellar atrophy, migraine, myogloblinuria and developmental delay. We describe a patient who presented with neonatal liver and pancreatic insufficiency, tyrosinemia and hyperammonemia and later developed sensorineural hearing loss and Leigh syndrome. Liver biopsy revealed markedly reduced complex I+III and II+III. Addition of CoQ to the liver homogenate restored the activities, suggesting CoQ depletion. Histological staining showed prominent bridging; septal fibrosis and widening of portal spaces with prominent mixed inflammatory infiltrate, associated with interface hepatitis, bile duct proliferation with numerous bile plugs. Electron microscopy revealed a large number of mitochondria, which were altered in shape and size, widened and disordered intercristal spaces. This may be the first case of Leigh syndrome with liver and pancreas insufficiency, possibly caused by CoQ responsive oxphos deficiency.
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PMID:Neonatal liver failure and Leigh syndrome possibly due to CoQ-responsive OXPHOS deficiency. 1294 44

Episodic ataxia type 2 (EA2) is a dominantly inherited disorder, characterized by spells of ataxia, dysarthria, vertigo, and migraines, associated with mutations in the neuronal calcium-channel gene CACNA1A. Ataxic spells lasting minutes to hours are provoked by stress, exercise, or alcohol. Some patients exhibit nystagmus between spells and some develop progressive ataxia later in life. At least 21 distinct CACNA1A mutations have been identified in EA2. The clinical and genetic complexities of EA2 have offered few insights into the underlying pathogenic mechanisms for this disorder. We identified a novel EA2 kindred in which members had ataxic spells induced by fevers or high environmental temperature. We identified a novel CACNA1A mutation (nucleotides 1253+1 G-->A) that was present in all subjects with febrile spells or ataxia. Moreover, we found that, regardless of age or interictal clinical status, all affected subjects had objective evidence of abnormal saccades, ocular fixation, and postural stability. These findings suggest that early cerebellar dysfunction in EA2 results from the intrinsically abnormal properties of the CACNA1A channel rather than a degenerative process.
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PMID:Novel CACNA1A mutation causes febrile episodic ataxia with interictal cerebellar deficits. 1468 82

The authors searched for mutations in CACNA1A in patients with episodic ataxia and describe the clinical spectrum in genetically defined patients. Eighteen families and nine sporadic cases of episodic ataxia were evaluated for mutations in CACNA1A. The families were first genotyped to check for linkage to the chromosome 19p locus of CACNA1A. In families consistent with linkage and in the sporadic cases, the authors screened for polymorphisms in CACNA1A using single-strand conformational polymorphism and denaturing high performance liquid chromatography followed by direct sequencing to identify specific nucleotide changes. Of the 18 families, 11 were linked to 19p and mutations were found in 9. Mutations were detected in four of the nine sporadic cases. Overall, five nonsense mutations, four missense mutations, two deletions, one insertion, and one donor splice mutation were identified. All but two of the 64 genetically defined patients reported episodes of ataxia (two members of one family only had progressive ataxia). All but one had onset before age 20 and all but four had interictal nystagmus. Migraine headaches occurred in more than half, and about two thirds reported a good response to treatment with acetazolamide. Vertigo and weakness accompanied the ataxia in more than half of the genetically defined patients. One family had multiple members with epilepsy. A wide range of mutations in CACNA1A were associated with episodic ataxia. Four of 13 were missense mutations; the remainder predicted truncated proteins. The mutations were scattered throughout the gene, and only 2 of the 13 mutations identified in our laboratory have been reported by other laboratories, so it will not be possible to screen a few "hot spots" in CACNA1A. Overall, the type of mutation, missense versus nonsense, or the location of altered or truncated amino acid residues did not predict the clinical phenotype.
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PMID:Clinical spectrum of episodic ataxia type 2. 1471 90

Numerous studies have shown the pathological influence anti-phospholipid antibodies (APLA) have on the physiology of the single neuron as well as the function of the entire human nervous system. The influence is well demonstrated in the antiphospholipid syndrome (APS). This syndrome is characterized by a triad of arterial or venous thrombotic events, recurrent fetal loss and thrombocytopenic purpura. The syndrome exhibits different neurological pathologies such as: chorea, seizures, transverse myelopathy, migraine, cerebral ataxia, hemiballismus and transient global amnesia, which are not fully explained by the procoagulopathic trait of APLA. A study on mice induced with APS demonstrated hyperactive behavior when compared to the control group. The information gathered from these different studies raised the question whether APLA has any part in the etiology of Attention Deficit/Hyperactive Disorder (ADHD) in children. We compared 41 children diagnosed with ADHD to a control of 28 healthy children. Blood drawn from the two groups was screened using ELISA for the presence of anti-cardiolipin antibodies, anti-beta2GP antibodies, anti-phosphatidyleserine antibodies and anti-ethanolamine antibodies. The results show no significant difference in the level of antiphospholipid antibodies (APLA) measured between the children diagnosed with ADHD and the control group.
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PMID:Lack of association between anti-phospholipid antibodies (APLA) and Attention Deficit/Hyperactivity Disorder (ADHD) in children. 1476 40

An abnormally expanded CAG repeats (25, normal; 4-20) was identified in the alpha 1A voltage-dependent calcium channel (CACNA1A) gene of a 50-year-old Japanese man with 25 years history of schizophrenia. At age 45, he first noted unsteadiness of standing and gait, which gradually worsened subsequently. In addition to the psychiatric symptoms of schizophrenia, neurological examination revealed marked truncal ataxia and mild limb ataxia. Brain magnetic resonance imaging showed atrophy of the cerebellar vermis. Gene analysis confirmed the diagnosis of spinocerebellar ataxia type 6 (SCA 6). No family members showed similar neuropsychiatric symptoms except that the patient's father had been suffering from an unknown dementing disease. Occurrence of both schizophrenia and SCA 6 in the identical patient may be coincidental. However, growing evidence has shown that various mutations in the CACNA1A gene are associated with phenotypic variability, such as progressive ataxia, episodic ataxia, migraine, coma, epilepsy and mental retardation. Therefore, the schizophrenic symptoms, association of which with SCA 6 has previously reported in a few cases, may represent rare clinical features of the channelopathy associated with the mutation in the CACNA1A gene.
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PMID:[A case of spinocerebellar ataxia 6 accompanied with schizophrenia]. 1502 29


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