Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 34-year-old man developed cerebellar symptoms, palatal myoclonus and spastic paraparesis progressing over several months. During this period, acute respiratory failure occurred in two instances with evidence of central chronic hypoventilation. CT scan showed enlargement of the frontal horns and posterior fossa cisterns. Post mortem examination revealed the following features: 1) Rosenthal's fibers widespread throughout the CNS but especially in subependymal regions; 2) bilateral white matter cavitations involving the frontal lobes, hilum of dentate nuclei and bulbar pyramids; 3) microscopic pseudogliomatous foci present in several sites, especially in the fornix and midbrain tegmentum; 4) the medulla and high cervical spinal cord showed "peripheral type" myelin fibers along with Schwann cell proliferation in aberrant intra-parenchymal situation. The relationship of this case--as well as the few previous adult reports--to the well-defined infantile Alexander's disease is discussed. The possible hamartomatous nature of both glial changes and aberrant myelin production is emphasized. These various lesions, including Rosenthal fiber formation, are assumed to result from a similar--probably dysontogenetic--pathophysiological mechanism. It is suggested that Alexander's disease, in this case, should be classified among phakomatoses rather than enzymopathic leukodystrophies.
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PMID:[Alexander's disease in an adult]. 672 28

Three siblings presented with a progressive neurological disorder beginning in the third decade of life and characterised by palatal myoclonus, nystagmus, bulbar weakness and spastic tetraparesis. There was no evidence of intellectual deterioration or seizures. CT scan showed marked brainstem atrophy in two patients and basal ganglia calcification in one. MRI scan in one showed high signal in the brainstem and periventricular region and cerebral biopsy in this patient showed myelin loss and the presence of Rosenthal fibres. A similar disease affected the siblings' mother, maternal aunt and two of the aunt's daughters, suggesting an autosomal dominant mode of transmission of what appears to be a unique genetic disorder.
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PMID:A familial disorder associated with palatal myoclonus, other brainstem signs, tetraparesis, ataxia and Rosenthal fibre formation. 841 38

We describe a progressive neurologic disorder in three sisters characterized clinically by palatal myoclonus, spastic weakness, hyperreflexia, mild cerebellar dysfunction, and ocular motor abnormalities. Postmortem examination of one patient demonstrated widespread Rosenthal fiber deposition associated with demyelination. The father previously was reported to have similar pathologic findings and carried a clinical diagnosis of multiple sclerosis. These clinical and pathologic findings describe a rare familial leukodystrophy that corresponds most closely to cases reported as adult Alexander's disease. Although similar pathologically to the well-characterized infantile variant of Alexander's disease, it is not known whether this adult variant represents the same disease process.
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PMID:Hereditary adult-onset Alexander's disease with palatal myoclonus, spastic paraparesis, and cerebellar ataxia. 904 Jul 73

We describe 2 new cases of Alexander's disease, the first to be reported in Belgium. The first patient, a 4-year-old girl, presented with progressive megalencephaly, mental retardation, spastic tetraparesis, ataxia and epilepsy: post-mortem examination showed widespread myelin loss with Rosenthal fibers (RFs) accumulation throughout the neuraxis. She was the third of heterozygotic twins, the 2 others having developed normally and being alive at age 5 years. The second patient developed at age 10 years and over a decade spastic paraparesis, palatal myoclonus, nystagmus, thoracic hyperkyphosis and thoraco-lumbar scoliosis with radiological findings of bilateral anterior leukoencephalopathy. Brain stereotactic biopsy at age 16 years demonstrated numerous RFs. With these 2 cases, we review the literature on the various clinico-pathological conditions reported as Alexander's disease. We discuss the nosology of this entity and the pathogeny of RFs formation and dysmyelination. Clues to the diagnosis of this encephalopathy in the living patient are briefly described.
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PMID:Infantile and juvenile presentations of Alexander's disease: a report of two cases. 1010 Sep 59

Alexander's disease, a leukodystrophy characterized by Rosenthal fibers (RFs) in the brain, is categorized into three subtypes: infantile, juvenile, and adult. Although most are sporadic, occasional familial Alexander's disease cases have been reported for each subtype. Hereditary adult-onset Alexander's disease shows progressive spastic paresis, bulbar or pseudobulbar palsy, palatal myoclonus symptomatologically, and prominent atrophy of the medulla oblongata and upper spinal cord on magnetic resonance imaging. Recent identification of GFAP gene mutations in the sporadic infantile- and juvenile-onset Alexander's disease prompted us to examine the GFAP gene in two Japanese hereditary adult-onset Alexander's disease brothers with autopsy in one case. Both had spastic paresis without palatal myoclonus, and magnetic resonance imaging showed marked atrophy of the medulla oblongata and cervicothoracic cord. The autopsy showed severely involved shrunken pyramids, but scarce Rosenthal fibers (RFs). Moderate numbers of Rosenthal fibers (RFs) were observed in the stratum subcallosum and hippocampal fimbria. In both cases, we found a novel missense mutation of a G-to-T transition at nucleotide 841 in the GFAP gene that results in the substitution of arginine for leucine at amino acid residue 276 (R276L). This is the first report of identification of the causative mutation of the GFAP gene for neuropathologically proven hereditary adult-onset Alexander's disease, suggesting a common molecular mechanism underlies the three Alexander's disease subtypes.
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PMID:Identification of GFAP gene mutation in hereditary adult-onset Alexander's disease. 1244 32

Alexander's disease, a rare and fatal disorder of the central nervous system, most commonly affects infants and young children but can also occur in older children and sometimes adults. In infants and young children, it causes developmental delay, psychomotor retardation, paraparesis, feeding problems, usually megalencephaly, often seizures, and sometimes hydrocephalus. Juvenile cases often do not have megalencephaly and tend to have predominant pseudobulbar and bulbar signs. In both groups, characteristic magnetic resonance imaging findings have been described. In adult cases, the signs are variable, can resemble multiple sclerosis, and might include palatal myoclonus. In all cases, the examination of brain tissue shows the presence of widely distributed Rosenthal fibers. Almost all cases have recently been found to have a heterozygous, missense, point mutation in the gene for glial fibrillary acidic protein, which provides a new diagnostic tool. In most cases, the mutation appears to occur de novo, not being present in either parent, but some adult cases are familial.
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PMID:Alexander's disease: clinical, pathologic, and genetic features. 1457 41

Alexander disease (AD) in its typical form is an infantile lethal leucodystrophy, characterized pathologically by Rosenthal fibre accumulation. Following the identification of glial fibrillary acidic protein (GFAP) gene as the causative gene, cases of adult-onset AD (AOAD) are being described with increasing frequency. AOAD has a different clinical and neuroradiological presentation with respect to early-onset AD, as abnormalities are mainly concentrated in the brainstem-spinal cord junction. We report detailed clinical and genetic data of 11 cases of AOAD, observed over a 4-year period, and a review of the previously reported 25 cases of genetically confirmed AOAD. In our series, onset occurred as late as age 62, and up to 71 in an affected deceased relative. Most cases appeared sporadic, but family history may be misleading. The most frequent symptoms were related to bulbar dysfunction-with dysarthria, dysphagia, dysphonia (seven patients)-, pyramidal involvement (seven patients) and cerebellar ataxia (seven patients). Four patients had palatal myoclonus. Sleep disorders were also observed (four cases). Bulbar symptoms, however, were infrequent at onset and two symptomatic patients had an almost pure pyramidal involvement. Two subjects were asymptomatic. Misdiagnosis at presentation was frequent and MRI was instrumental in suggesting the correct diagnosis by showing, in all cases, mild to severe atrophy of the medulla oblongata extending caudally to the cervical spinal cord. In ten patients, molecular studies revealed six novel missense mutations and three previously reported changes in GFAP. The last typical patient carried no definitely pathogenic mutation, but a missense variant (p.D157N), supposedly a rare polymorphism. Revision of the literature and the present series indicate that the clinical picture is not specific, but AOAD must be considered in patients of any age with lower brainstem signs. When present, palatal myoclonus is strongly suggestive. Pyramidal involvement, cerebellar ataxia and urinary disturbances are common. Less frequent findings include sleep disorders and dysautonomia. Fluctuations may occur. The course is variable, usually slowly progressive and less severe than the AD forms with earlier onset. AOAD is more common than previously thought and might even be the most common form of AD. The diagnosis is strongly suggested by MRI and confirmed by GFAP gene analysis.
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PMID:Adult-onset Alexander disease: a series of eleven unrelated cases with review of the literature. 1868 70

Alexander Disease (AxD) is a "gliopathy" caused by toxic, dominant gain-of-function mutations in the glial fibrillary acidic protein (GFAP) gene. Two distinct types of AxD exist. Type I AxD affected individuals develop cerebral symptoms by 4 years of age and suffer from macrocephaly, seizures, and physical and mental delays. As detection and diagnosis have improved, approximately half of all AxD patients diagnosed have onset >4 years and brainstem/spinal cord involvement. Type II AxD patients experience ataxia, palatal myoclonus, dysphagia, and dysphonia. No study has examined a mechanistic link between the GFAP mutations and caudal symptoms present in type II AxD patients. We demonstrate that two key astrocytic functions, the ability to regulate extracellular glutamate and to take up K(+) via K+ channels, are compromised in hindbrain regions and spinal cord in AxD mice. Spinal cord astrocytes in AxD transgenic mice are depolarized relative to WT littermates, and have a three-fold reduction in Ba(2+) -sensitive Kir4.1 mediated currents and six-fold reduction in glutamate uptake currents. The loss of these two functions is due to significant decreases in Kir4.1 (>70%) and GLT-1 (>60%) protein expression. mRNA expression for KCNJ10 and SLC1A2, the genes that code for Kir4.1 and GLT-1, are significantly reduced by postnatal Day 7. Protein and mRNA reductions for Kir4.1 and GLT-1 are exacerbated in AxD models that demonstrate earlier accumulation of GFAP and increased Rosenthal fiber formation. These findings provide a mechanistic link between the GFAP mutations/overexpression and the symptoms in those affected with Type II AxD.
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PMID:Elevated GFAP induces astrocyte dysfunction in caudal brain regions: A potential mechanism for hindbrain involved symptoms in type II Alexander disease. 2619 Apr 8