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)

To date, at least 12 types of primary dystonia can be distinguished on a genetic basis. A 3-bp deletion in the DYT1 gene causes early onset, generalized torsion dystonia (TD), and mutations in the GTP cyclohydrolase I and the tyrosine hydroxylase genes result in dopa-responsive dystonia (DYT5). A missense change in the D2 dopamine receptor in one large family (DYT11) has recently been implicated in myoclonus-dystonia. Furthermore, seven other loci for dystonia genes have been mapped to chromosomal regions, including a locus for a mixed dystonia phenotype (DYT6), one form of focal dystonia (DYT7), three types of paroxysmal dystonia (DYT8-10), X-linked dystonia-parkinsonism (DYT3), and rapid-onset dystonia-parkinsonism (DYT12). No positive linkage results have yet been obtained for autosomal recessive TD (DYT2) and several other families of different types of dominantly inherited TD (DYT4). In addition, hereditary secondary dystonia may occur as part of familial diseases of the basal ganglia, metabolic and storage disorders, and various X-linked and other familial neurodegenerative syndromes affecting the basal ganglia. It may be anticipated that the traditional clinical and etiological classifications of dystonia will increasingly be replaced by a genetic one and that the identification of more dystonia genes may lead to a better understanding of these largely nondegenerative disorders.
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PMID:[Genetics of dystonia]. 1091 37

Dystonia is an interesting disorder characterized by involuntary movement of the body part or parts leading to abnormal deformed postures. The usual signs and symptoms are local pain, spasm and abnormal movements. Sensory trick is an important clinical phenomenon and is characteristic of dystonia. It is usually separated from other movement disorders such as chorea, athetosis, tics and myoclonus clinically. Various non-dystonic conditions simulate dystonia and need to be separated in view of different line of management. Improved understanding in molecular biology has helped in understanding of the disease. Confusing neuropathology and neurochemistry have deterred the finding of an effective drug, however empirical use of few drugs have improved the gloomy situation. Few conditions such as dopa-responsive dystonia have definite treatment. Recently use of botulinum toxin has provided beneficial response in hyper muscular contraction states such as dystonia and spasticity, Surgery and other non-medical therapies are effective in few situations.
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PMID:A spectrum of dystonias-clinical features and update on management. 1127 44

The dystonias are a common clinically and genetically heterogeneous group of movement disorders. More than ten loci for inherited forms of dystonia have been mapped, but only three mutated genes have been identified so far. These are DYT1, encoding torsin A and mutant in the early-onset generalized form, GCH1 (formerly known as DYT5), encoding GTP-cyclohydrolase I and mutant in dominant dopa-responsive dystonia, and TH, encoding tyrosine hydroxylase and mutant in the recessive form of the disease. Myoclonus-dystonia syndrome (MDS; DYT11) is an autosomal dominant disorder characterized by bilateral, alcohol-sensitive myoclonic jerks involving mainly the arms and axial muscles. Dystonia, usually torticollis and/or writer's cramp, occurs in most but not all affected patients and may occasionally be the only symptom of the disease. In addition, patients often show prominent psychiatric abnormalities, including panic attacks and obsessive-compulsive behavior. In most MDS families, the disease is linked to a locus on chromosome 7q21 (refs. 11-13). Using a positional cloning approach, we have identified five different heterozygous loss-of-function mutations in the gene for epsilon-sarcoglycan (SGCE), which we mapped to a refined critical region of about 3.2 Mb. SGCE is expressed in all brain regions examined. Pedigree analysis shows a marked difference in penetrance depending on the parental origin of the disease allele. This is indicative of a maternal imprinting mechanism, which has been demonstrated in the mouse epsilon-sarcoglycan gene.
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PMID:Mutations in the gene encoding epsilon-sarcoglycan cause myoclonus-dystonia syndrome. 1152 94

Dystonias are a heterogeneous group of disorders which are known to have a strong inherited basis. This review details recent advances in our understanding of the genetic basis of dystonias, including the primary dystonias, the 'dystonia-plus' syndromes and heredodegenerative disorders. The review focuses particularly on clinical and genetic features and molecular mechanisms. Conditions discussed in detail include idiopathic torsion dystonia (DYT1), focal dystonias (DYT7) and mixed dystonias (DYT6 and DYT13), dopa-responsive dystonia, myoclonus dystonia, rapid-onset dystonia parkinsonism, Fahr disease, Aicardi-Goutieres syndrome, Hallervorden-Spatz syndrome, X-linked dystonia parkinsonism, deafness-dystonia syndrome, mitochondrial dystonias, neuroacanthocytosis and the paroxysmal dystonias/dyskinesias.
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PMID:The genetics of primary dystonias and related disorders. 1191 6

Currently, at least 12 types of dystonia can be distinguished on a genetic basis. Advances in the molecular genetics of dystonia have led to the recent identification of a 3-bp deletion in the DYT1 gene, causing early-onset generalized torsion dystonia (TD), and to the detection of mutations in the GTP cyclohydrolase I and the tyrosine hydroxylase genes causing dopa-responsive dystonia (DYT5). A missense change in the D2 dopamine receptor has been shown to be associated with myoclonus-dystonia in one family. In addition, six other dystonia gene loci have been mapped to chromosomal regions, including a locus for a mixed dystonia phenotype (DYT6), one form of focal dystonia (DYT7), two types of paroxysmal dystonia (DYT8, DYT9), X-linked dystonia-parkinsonism (DYT3), and rapid-onset dystonia parkinsonism (DYT12). No positive linkage studies have as yet been reported for autosomal recessive TD (DYT2) and in several other large families with various types of dominantly inherited TD (DYT4). It may be anticipated that the traditional clinical and etiological classifications of dystonia will increasingly be replaced by a genetic one and that the identification of more dystonia genes may lead to a better understanding of these largely nondegenerative disorders.
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PMID:Genetics of primary dystonia. 1219 83

The authors report a kindred in which GTP-CH deficiency resulted in a myoclonus-dystonia syndrome. The proband, a 17-year-old boy, presented with early-onset myoclonus and later, dystonia and bradykinesia. Blood prolactin was increased and CSF homovanillic acid, 5-hydroxyindoleacetic acid, and biopterin were all reduced. L-Dopa/carbidopa administration resulted in clinical improvement. In the paternal branch, the grandfather and three relatives had myoclonus-dystonia and resting or postural tremor of limbs. The authors found a missense mutation in the exon 6 of GCH-1 gene (K224R).
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PMID:Autosomal dominant GTP-CH deficiency presenting as a dopa-responsive myoclonus-dystonia syndrome. 1239 38

Childhood dystonias are a heterogeneous group of disorders with strong inherited basis. This review describes the clinical characteristics, classification, genetic basis, pathophysiology, biochemistry, pathology, and treatment of dystonias, including the primary dystonias, the dystonia-plus syndromes, secondary dystonias, and heredodegenerative disorders. Conditions discussed in detail include idiopathic torsion dystonia, dopa-responsive dystonia, Wilson's disease, myoclonus dystonia, rapid-onset dystonia parkinsonism, neurodegeneration with brain iron accumulation (Hallervorden-Spatz syndrome), mitochondrial dystonias, Niemann-Pick type C, and neuroacanthocytosis.
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PMID:Childhood dystonia. 1278 48

Because of the occurrence of different types of mutations, comprehensive genetic testing for Parkinson's disease (PD), dopa-responsive dystonia (DRD), and myoclonus-dystonia (M-D) should include screening for small sequence changes and for large exonic rearrangements in disease-associated genes. In diagnostic and research settings, the latter is frequently omitted or performed by laborious and expensive quantitative real-time PCR (qPCR). Our study aimed to evaluate the utility of a novel method, multiplex ligation-dependent probe amplification (MLPA), in molecular diagnostics of movement disorders. We have analyzed, by MLPA, genomic DNA from 21 patients affected with PD, DRD, or M-D, in which the presence of exon rearrangement(s) (n = 20) or of a specific point mutation (detectable by MLPA, n = 1) had been established previously by qPCR or sequencing. In parallel, we have studied, in a blinded fashion, DNA from 49 patients with an unknown mutational status. Exon rearrangements were evident in 20 samples with previously established mutations; in the 21st sample the known specific point mutation was detected. We conclude that MLPA represents a reliable method for large-scale and cost-effective gene dosage screening of various movement disorders genes. This finding reaches far beyond a simple technical advancement and has two major implications: (1) By improving the availability of comprehensive genetic testing, it supports clinicians in the establishment of a genetically defined diagnosis; (2) By enabling gene dosage testing of several genes simultaneously, it significantly facilitates the mutational analysis of large patient and control populations and thereby constitutes the prerequisite for meaningful phenotype-genotype correlations.
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PMID:Rapid and reliable detection of exon rearrangements in various movement disorders genes by multiplex ligation-dependent probe amplification. 1767 14

The torsion dystonias encompass a broad collection of etiologic subtypes, often divided into primary and secondary classes. Over the last two decades an increasing number of genetic causes have been identified, including an important genetic cause for early-onset primary torsion dystonia (PTD): a GAG deletion in exon 5 of DYT1, a gene that encodes torsinA. Although the exact function of torsinA remains elusive, evidence suggests aberrant localization and interaction of mutated protein; this may result in an abnormal response to stress or interference with cytoskeletal events and the development of neuronal brain pathways. Identification of DYT1 has also permitted studies of both "manifesting" and "non-manifesting"DYT1 mutation carriers. These investigations have expanded our understanding of clinical expression to include psychiatric symptoms and also have enabled imaging studies of endophenotypes. Similarly, there has been progress in our understanding of the genetic underpinnings of the "dystonia-plus" syndromes: dopa-responsive dystonia (DRD), myoclonus-dystonia (M-D), and rapid-onset dystonia-parkinsonism (RDP). These advances provide a widened platform for future research.
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PMID:Genetics of dystonia: an overview. 1826 63

Presently, 17 distinct monogenic primary dystonias referred to as dystonias 1- 4, 5a,b, 6-8, 10-13 and 15-18 (loci DYT 1-4, 5a,b, 6-8, 10-13, 15-18) have been recognized. Twelve forms are inherited as autosomal dominant, four as autosomal recessive and one as an X-linked recessive trait. Three additional autosomal dominant forms (DYT9, DYT19 and DYT20) might exist based on linkage mapping to regions apparently different from, yet in close proximity to or overlapping with the known loci DYT18, DYT10 and DYT8. Clinically, this group of movement disorders includes pure dystonias and dystonia plus syndromes. In addition, dyskinesias (paroxysmal dystonias), although phenotypically distinct from classical dystonias, are discussed within this group. In pure dystonias, dystonia is occasionally accompanied by tremor. In dystonia plus syndromes, dystonia as the prominent sign concurs with other movement abnormalities such as myoclonus and parkinsonism. In the dyskinesias, dystonia occurs as a paroxysmal sign in association with other movement anomalies and sometimes seizures. While gross neuropathological changes are absent in most primary dystonias, including the paroxysmal forms, striking morphological alterations are found in some, such as in the X-linked dystonia-parkinsonism syndrome (DYT3). Neuropathological findings at the microscopic level have also been reported in several cases of dystonia 1 and 5, both of which were previously thought to be morphologically normal. One locus, DYT14 had been erroneously assigned, by linkage mapping, in a family with dystonia 5. There are two forms of dystonia 5, one autosomal dominant and one autosomal recessive. These forms are designated here as dystonia 5a and dystonia 5b (DYT5a, DYT5b), respectively. The disease gene has been identified in 10 primary dystonias, seven autosomal dominant (TOR1A/DYT1, GCH1/DYT5a, THAP1/DYT6, PNKD1/MR-1/DYT8, SGCE/DYT11, ATP1A3/DYT12 and SLC2A1/DYT18), two autosomal recessive (TH/DYT5b and PRKRA/DYT16) and one X-chromosomal recessive (TAF1/DYT3). This article summarizes all known aspects on each of the monogenic primary dystonias, including phenotype, neuropathology, imaging, inheritance, mapping, molecular genetics, molecular pathology, animal models and treatment. Suggestions for the diagnostic procedure in primary dystonias are given. Although much is now known about the molecular basis of primary dystonias, treatment of patients is still mainly symptomatic. The only exceptions are dystonias 5a and 5b with their excellent long-term response to L-dopa substitution.
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PMID:The monogenic primary dystonias. 1957 24


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