Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0013421 (dystonia)
 8,418 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extrapyramidal features may occur in spinocerebellar ataxias consistent with neuropathological evidence of nigrostriatal involvement. Recently, striatal dopaminergic neurotransmission was found to be abnormal in the uncommon parkinsonian presentation of spinocerebellar ataxia type 2 (SCA2). We have investigated, therefore, striatal dopamine transporter and D2 receptor function in a series of 9 patients with the more common ataxic presentation of SCA2 using single photon emission computed tomography and beta-CIT as well as IBZM. Age-matched healthy subjects and patients with Parkinson's disease (PD) served as controls. All except 1 SCA2 patient exhibited slowness of limb movements without rigidity or rest tremor. In addition, cervical dystonia was present in 5 and dystonic head tremor in 2 SCA2 patients. Striatocerebellar (S/C) ratios of beta-CIT binding were significantly reduced in SCA2 patients compared to control subjects, and they were within the range of PD patients. S/C ratios of IBZM binding were significantly reduced in SCA2 patients compared to control subjects. We conclude that dopaminergic neurotransmission is impaired in the ataxic presentation of SCA2, with a prominent loss of striatal dopamine transporter function. Both slowness of limb movements as well as dystonia in the ataxic SCA2 phenotype may reflect dysfunction not only at cerebellar but also at basal ganglia level.
 ...
PMID:Abnormalities of dopaminergic neurotransmission in SCA2: a combined 123I-betaCIT and 123I-IBZM SPECT study. 1539 3

Most cases of early-onset torsion dystonia (EOTD) are caused by a deletion of one glutamic acid in the carboxyl terminus of a protein named torsinA. The mutation causes the protein to aggregate in perinuclear inclusions as opposed to the endoplasmic reticulum localization of the wild-type protein. Although there is increasing evidence that dysfunction of the dopamine system is implicated in the development of EOTD, the biological function of torsinA and its relation to dopaminergic neurotransmission has remained unexplored. Here, we show that torsinA can regulate the cellular trafficking of the dopamine transporter, as well as other polytopic membrane-bound proteins, including G protein-coupled receptors, transporters, and ion channels. This effect was prevented by mutating the ATP-binding site in torsinA. The dystonia-associated torsinA deletion mutant (DeltaE-torsinA) did not have any effect on the cell surface distribution of polytopic membrane-associated proteins, suggesting that the mutation linked with EOTD results in a loss of function. However, a mutation in the ATP-binding site in DeltaE-torsinA reversed the aggregate phenotype associated with the mutant. Moreover, the deletion mutant acts as a dominant-negative of wild-type torsinA through a mechanism presumably involving association of wild-type and mutant torsinA. Taken together, our results provide evidence for a functional role for torsinA and a loss of function and a dominant-negative phenotype of the DeltaE-torsinA mutation. These properties may contribute to the autosomal dominant nature of the condition.
 ...
PMID:Effect of torsinA on membrane proteins reveals a loss of function and a dominant-negative phenotype of the dystonia-associated DeltaE-torsinA mutant. 1550 7

A 35-year-old female ingested a lethal dose of potassium cyanide in a suicide attempt. She survived following antidote therapy and intensive care. Following artificial coma she presented with an agitative state for several days followed by akinetic mutism, buccofacial and ideomotoric aphasia. Severe rigid-akinetic syndrome, dysarthria, dysphagia and generalized dystonia developed weeks later. MRI revealed lesions in the caudate and lentiform nuclei, precentral cortex, and cerebellum. SPECT by [123-I] 2 beta-carbomethoxy-3-beta-(4-iodophenyl)-Tropan on two occasions revealed progressive loss of dopamine transporter suggestive of nigral neuronal apoptosis. Striatal and frontal hypometabolism and hypoperfusion were found by FDG-PET and HMPAO SPECT.
 ...
PMID:Cyanide-induced akinetic rigid syndrome: clinical, MRI, FDG-PET, beta-CIT and HMPAO SPECT findings. 1573 73

Parkinson's disease (PD) is linked genetically to proteins that function in the management of cellular stress resulting from protein misfolding and oxidative damage. Overexpression or mutation of alpha-synuclein results in the formation of Lewy bodies and neurodegeneration of dopaminergic (DA) neurons. Human torsinA, mutations in which cause another movement disorder termed early-onset torsion dystonia, is highly expressed in DA neurons and is also a component of Lewy bodies. Previous work has established torsins as having molecular chaperone activity. Thus, we examined the ability of torsinA to manage cellular stress within DA neurons of the nematode Caenorhabditis elegans. Worm DA neurons undergo a reproducible pattern of neurodegeneration after treatment with 6-hydroxydopamine (6-OHDA), a neurotoxin commonly used to model PD. Overexpression of torsins in C. elegans DA neurons results in dramatic suppression of neurodegeneration after 6-OHDA treatment. In contrast, expression of either dystonia-associated mutant torsinA or combined overexpression of wild-type and mutant torsinA yielded greatly diminished neuroprotection against 6-OHDA. We further demonstrated that torsins seem to protect DA neurons from 6-OHDA through downregulating protein levels of the dopamine transporter (DAT-1) in vivo. Additionally, we determined that torsins protect robustly against DA neurodegeneration caused by overexpression of alpha-synuclein. Using mutant nematodes lacking DAT-1 function, we also showed that torsin neuroprotection from alpha-synuclein-induced degeneration occurs in a manner independent of this transporter. Together, these data have mechanistic implications for movement disorders, because our results demonstrate that torsin proteins have the capacity to manage sources of cellular stress within DA neurons.
 ...
PMID:Torsin-mediated protection from cellular stress in the dopaminergic neurons of Caenorhabditis elegans. 1582 32

Early onset torsion dystonia (EOTD) is a rare movement disorder characterized by involuntary, repetitive, sustained muscle contractions or postures involving one or more sites of the body. A US study estimated the prevalence at approximately 1 in 30,000. The estimated prevalence in the general population of Europe seems to be lower, ranging from 1 in 330,000 to 1 in 200,000, although precise numbers are currently not available. The estimated prevalence in the Ashkenazi Jewish population is approximately five to ten times higher, due to a founder mutation. Symptoms of EOTD typically develop first in an arm or leg in middle to late childhood and progress in approximately 30% of patients to other body regions (generalized dystonia) within about five years. Distribution and severity of symptoms vary widely between affected individuals. The majority of cases from various ethnic groups are caused by an autosomal dominantly inherited deletion of 3 bp (GAG) in the DYT1 gene on chromosome 9q34. This gene encodes a protein named torsinA, which is presumed to act as a chaperone protein associated with the endoplasmic reticulum and the nuclear envelope. It may interact with the dopamine transporter and participate in intracellular trafficking, although its precise function within the cell remains to be determined. Molecular genetic diagnostic and genetic counseling is recommended for individuals with age of onset below 26 years, and may also be considered in those with onset after 26 years having a relative with typical early onset dystonia. Treatment options include botulinum toxin injections for focal symptoms, pharmacological therapy such as anticholinergics (most commonly trihexiphenydil) for generalized dystonia and surgical approaches such as deep brain stimulation of the internal globus pallidus or intrathecal baclofen application in severe cases. All patients have normal cognitive function, and despite a high rate of generalization of dystonia, 75% of those patients are able to maintain ambulation and independence, and therefore a comparatively good quality of life, with modern treatment modalities.
 ...
PMID:Early onset torsion dystonia (Oppenheim's dystonia). 1712 79

We present the clinical details and dopamine transporter SPECT scan results of 10 patients with arm tremor, including a rest component and reduced arm swing on the affected side, in whom the possibility of PD had been raised. All patients had signs of dystonia or components of their arm tremor that were compatible with dystonic tremor, and none had true akinesia with fatiguing or decrement, even after a mean follow-up period of 5.8 years. All patients had normal dopamine transporter SPECT scans. Clinicians should be aware that primary adult-onset dystonia can present with an asymmetric resting arm tremor, with impaired arm swing and sometimes also facial hypomimia or a jaw tremor, but without evidence of true akinesia. Given the important consequences of misdiagnosing such patients as PD, in cases with diagnostic uncertainty functional imaging should be considered. Among patients suspected of PD, dystonic tremor may be one cause of SWEDDs (Scans Without Evidence of Dopaminergic Deficit).
 ...
PMID:Patients with adult-onset dystonic tremor resembling parkinsonian tremor have scans without evidence of dopaminergic deficit (SWEDDs). 1771 58

Ataxia with oculomotor apraxia type 1 (AOA1) is a rare autosomal recessive neurodegenerative disease, recently associated with mutations in the aprataxin gene. Main features are early onset cerebellar ataxia, oculomotor apraxia and peripheral neuropathy. The presence of choreoathetosis or dystonia in some patients suggests basal ganglia involvement, but these structures appear preserved in a single case in which neuropathological examination was performed. To evaluate in vivo the nigrostriatal function we studied dopamine transporter (DAT) density with [(123)I] 2beta-carbometoxy-3beta-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (FPCIT)-SPECT in four AOA1 patients and eight healthy volunteers. All patients showed ataxia and neuropathy; only one had chorea and none had dystonia. Comparing with controls, AOA1 patients showed a slight reduction of the average striatal DAT density, which was bilateral and uniform in caudate and putamen. Nigrostriatal impairment occurred even in the absence of extrapyramidal features. Our data suggest subclinical involvement of basal ganglia in AOA1.
 ...
PMID:Nigrostriatal involvement in ataxia with oculomotor apraxia type 1. 1800 40

A neurological syndrome characterized by levodopa unresponsive bradykinesia, retropulsion with falls backwards, dysarthria, gait disturbance, dystonia, and emotional lability was identified in 13 male opiate addicts following the prolonged intravenous use of ephedrone (methcathinone), a central nervous stimulant prepared from pseudoephedrine, potassium permanganate, and vinegar. The natural history, response to treatment, and clinical features has been studied, and MR and dopamine transporter SPECT brain imaging were carried out. Pubic hair was sampled for manganese. The clinical and radiological picture closely resembled previous reports of chronic manganese poisoning and increased mean manganese level in pubic hair observed for at least 1 year after cessation of ephedrone. Odor identification was intact. Cognitive assessment showed a mild executive dysfunction and a mild depression. DaTSCANs were all normal. The neurological syndrome bears some similarities to PSP but differs from Parkinson's disease. Delayed neurological progression despite discontinuation of ephedrone occurred in one-third of cases. Ephedrone poisoning should be considered as a possible cause of secondary Parkinsonism in young adults, particularly from Eastern Europe.
 ...
PMID:Parkinsonism and dystonia caused by the illicit use of ephedrone--a longitudinal study. 1878 45

Genetic variants of the SLC6A3 gene that encodes the human dopamine transporter (DAT) have been linked to a variety of neuropsychiatric disorders, particularly attention deficit hyperactivity disorder. In addition, the homozygous Slc6a3 knockout mouse displays a hyperactivity phenotype. Here, we analyzed 2 unrelated consanguineous families with infantile parkinsonism-dystonia (IPD) syndrome and identified homozygous missense SLC6A3 mutations (p.L368Q and p.P395L) in both families. Functional studies demonstrated that both mutations were loss-of-function mutations that severely reduced levels of mature (85-kDa) DAT while having a differential effect on the apparent binding affinity of dopamine. Thus, in humans, loss-of-function SLC6A3 mutations that impair DAT-mediated dopamine transport activity are associated with an early-onset complex movement disorder. Identification of the molecular basis of IPD suggests SLC6A3 as a candidate susceptibility gene for other movement disorders associated with parkinsonism and/or dystonic features.
 ...
PMID:Homozygous loss-of-function mutations in the gene encoding the dopamine transporter are associated with infantile parkinsonism-dystonia. 1950 20

The dopamine transporter (DAT) retrieves the neurotransmitter dopamine from the synaptic cleft at dopaminergic synapses. Variations in solute carrier family 6A, member 3 (SLC6A3/DAT1), the human gene encoding DAT, have been implicated in attention deficit hyperactivity and bipolar disorders, and DAT is a prominent site of action for drugs such as amphetamines and cocaine. In this issue of the JCI, Kurian et al. report that an autosomal recessive infantile parkinsonism-dystonia is caused by loss-of-function mutations in DAT that impair dopamine reuptake (see the related article beginning on page 1595). Though this might be predicted to result in dopamine excess in the synaptic cleft, it likely also causes depletion of presynaptic dopamine stores and possibly downregulation of postsynaptic dopamine receptor function, resulting in impairments in dopaminergic neurotransmission consistent with the clinical presentation. This is the first report of a genetic alteration in DAT function underlying a parkinsonian disorder.
 ...
PMID:Infantile parkinsonism-dystonia: a dopamine "transportopathy". 1947 60


<< Previous 1 2 3 4 5 Next >>