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Query: UMLS:C0013421 (dystonia)
 8,418 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dystonia is a heterogeneous, neurological disease characterized by involuntary, sustained muscle contractions, frequently causing twisting and repetitive movements or abnormal postures. The patients are often difficult to diagnose, and the treatment is almost always only symptomatic. It is believed that about 75% of all patients with dystonia have primary dystonia, and 25-85% of these are hereditary. Seven gene loci for autosomal, dominant inherited dystonia and two for X-linked, recessive inherited dystonia are known at present, but the underlying genes are known only for DYT1 and DYT5. Testing is possible for these two in Denmark. Growing molecular genetic knowledge will lead to earlier and correct diagnosing, including prognosis, and may elucidate the pathogenesis, making better treatment possible.
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PMID:[Hereditary dystonias]. 1101 35

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

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

Hereditary progressive dystonia with marked diurnal fluctuation/dopa-responsive dystonia (HPD/DRD) shows the considerable heterogeneity of clinical phenotypic expression and a dramatic sustained response to levodopa. The autosomal dominant HPD/DRD is caused by mutations in the gene coding GTP cyclohydrolase I (GCH I), the enzyme that catalyzes the first step in the biosynthesis of tetrahydrobiopterin. Previous studies suggested that normal [18F]Dopa positron emission tomography or [123I]beta-CIT single-photon emission computed tomography (SPECT) imaging, indicating intact structural integrity of nigrostriatal neurons, may be useful for differentiating HPD/DRD from clinically similar conditions such as juvenile Parkinson's disease with dystonia that have a considerably poorer prognosis. We here report a Korean family affected with HPD/DRD due to a novel missense mutation of the GCH I gene (T-->G mutation in exon 2), Met 137 Arg, which may change the conformation of the binding site of GCH I. The clinical features are considerably variable within the family. We documented normal striatal uptake of [123I]IPT, a dopamine transporter ligand with fast washout kinetics, in our patients by using SPECT. This method can be helpful in diagnosing HPD/DRD in uncertain cases.
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PMID:A novel missense mutation of the GTP cyclohydrolase I gene in a Korean family with hereditary progressive dystonia/dopa-responsive dystonia. 1516 67

The hph-1 ENU-mutant mouse provides a model of tetrahydrobiopterin deficiency for studying hyperphenylalaninaemia, dopa-response dystonia, and vascular dysfunction. We have successively localized the hph-1 mutation to a congenic interval of 1.6-2.8 Mb, containing the GCH gene encoding GTP cyclohydrolase I (GTP-CH I). We used these data to establish a PCR method for genotyping wild type, hph-1 and heterozygote mice, and found that heterozygote animals have partial tetrahydrobiopterin deficiency. These new findings will extend the utility of the hph-1 mouse in studies of GTP-CH I deficiency.
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PMID:Congenic mapping and genotyping of the tetrahydrobiopterin-deficient hph-1 mouse. 1523 40

We describe the clinical and molecular correlates in two Italian families with dopa-responsive dystonia (DRD) and the same novel mutation of GTP-cyclohydrolase I (GCH-I) gene. Thirty-five subjects were examined and the genotype correlated to phenotype. Childhood onset foot dystonia is present in 7 subjects currently under the age of 40. In 1 patient bilateral foot dystonia was evident at birth suggesting that dystonia may be active as early as in utero. In another patient, dystonia spontaneously remitted in adolescence, to relapse 8 years later, as writer's cramp. Dystonia and parkinsonian signs are present in 5 other patients. In 2 subjects an isolated parkinsonism started over the age of 45. A 5-base pair insertion at codon 242 within exon 6 of GTP-cyclohydrolase I (GCH-I) gene that shifts the reading frame and results in a premature stop at codon 247 with truncation of the polypeptide has been detected in 21 subjects. Considering dystonia and parkinsonism the overall penetrance is 0.71 and not significantly different in men (0.69) and women (0.75). Genealogical studies seem to exclude that these families are related but haplotype analysis suggests a single founder. Our findings in subjects with the same mutation indicate a wide intrafamilial variation in expressivity and high penetrance in DRD but do not confirm the reported influence of gender on GCH-I gene mutation penetrance.
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PMID:Wide expressivity variation and high but no gender-related penetrance in two dopa-responsive dystonia families with a novel GCH-I mutation. 1539 21

Among idiopathic dystonia, inherited dystonia whose causative gene or linkage has been clarified are named as DYT1 to DYT15. The causative genes of DYT1, 5 and 11 were identified as genes of Torsin A, GTP cyclohydrolase I, and epsilon-sarcoglycan, respectively. All three are inherited dominantly. DYT1, and DYT5 which is known as Segawa disease, are dystonia with onset in childhood. After identification of the causative gene, each disorder was found to show the various phenotypes. In both DYT1 and Segawa disease, early onset develops generalized dystonia, and later onset focal or segmental dystonia. Deep brain stimulation of globus pallidus internal segment shows remarkable effect on DYT1. Segawa disease responds markedly to L-dopa without any side effect lifelong. The pathophysiology of Segawa disease is that partial deficiency of BH4 resulted from GCH I deficiency, rate limiting enzyme of synthesis of BH4, affects the TH activity at terminal of nigrostriatal dopamine neuron. The role of Torsin A in the pathogenesis of DYT1 is unknown. For a certain neuron or neuronal system to manifest a clinical symptom, it should reach to a certain maturational level. The symptoms of inherited dystonia are influenced by the developmental level of responsible neuron or neuronal circuit.
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PMID:[Inherited dystonia update]. 1565 34

Primary dystonia is a movement disorder characterized by involuntary and sustained muscle contractions causing twisting or abnormal postures and mutations in several genes have been identified. Our goal was to investigate, whether the clinical presentation would differ between patients with a positive family history, and patients without. Furthermore, we have performed mutation analysis in the subgroup of patients with a positive family history. A total of 175 patients with primary dystonia were evaluated. Data on gender, presence and frequency of pain and tremor, age of onset, and the distribution of affected body parts were compared between patients with positive and negative family history. All exons of the torsion dystonia 1, GTP cyclohydrolase 1 and epsilon-sarcoglycan genes were examined in 40 patients by SSCP analysis of PCR products followed by sequencing of variant conformers. Dystonia patients with a positive family history of dystonia had an earlier age of onset and those with a positive family history of tremor more often associated tremor than those with a negative family history. Four new polymorphisms in the epsilon-sarcoglycan gene were found and others confirmed, but no known or new mutations could be detected. Our study supports the notion that primary dystonia is a genetically heterogeneous disease.
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PMID:Clinical and molecular genetic evaluation of patients with primary dystonia. 1567 1

Dystonia is a syndrome which is characterized by sustained muscle contractions, producing twisting, repetitive, and patterned movements, or abnormal postures. According to genetic basis, dystonia is classified into 13 subtypes. We mainly discussed two subtypes, DYT1 and DYT5, in this review. Early-onset primary dystonia is caused by the mutation of DYT1 gene, which leads to TORSINA abnormal. GTP cyclohydrolase 1 (GTPCH1)-deficient DRD (DYT5) is caused by the mutations of GCH1 gene. By genetic testing, we can confirm clinical diagnosis of each subtype and develop prenatal diagnosis for it.
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PMID:Clinical and genetic features of DYT1 and DYT5. 1641 80

A 33-year-old woman developed exercise-induced limb and trunk dystonia with marked diurnal fluctuations. Treatment with levodopa improved her symptoms considerably but incompletely. Molecular genetic analysis revealed a mutation in GTP cyclohydrolase 1 (GCH1). This report illustrates the variability of Segawa disease and underlines the importance of a levodopa test in patients with uncommon dystonic symptoms.
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PMID:Adult-onset dystonia: atypical manifestation of Segawa disease. 1751 74


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