Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There has been an increase of interest in olfactory dysfunction since it was realised that anosmia was a common feature of idiopathic Parkinson's disease (PD) and Alzheimer-type dementia (AD). It is an intriguing possibility that the first sign of a disorder hitherto regarded as one of movement or cognition may be that of disturbed smell sense. In this review of PD, parkinsonian syndromes, essential tremor, AD, motor neurone disease (MND) and Huntington's chorea (HC) the following observations are made: 1). olfactory dysfunction is frequent and often severe in PD and AD; 2). normal smell identification in PD is rare and should prompt review of diagnosis unless the patient is female with tremor-dominant disease; 3). anosmia in suspected progressive supranuclear palsy and corticobasal degeneration is atypical and should likewise provoke diagnostic review; 4). hyposmia is an early feature of PD and AD and may precede motor and cognitive signs respectively; 5). subjects with anosmia and one ApoE-4 allele have an approximate 5-fold increased risk of later AD; 6). impaired smell sense is seen in some patients at 50% risk of parkinsonism; 7). smell testing in HC and MND where abnormality may be found, is not likely to be of clinical value; and 8). biopsy of olfactory nasal neurons shows non-specific changes in PD and AD and at present will not aid diagnosis.
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PMID:Olfaction in neurodegenerative disorder. 1267 41

Parkinsonism plus syndrome is a group of heterogeneous degenerative neurological disorders, which differ from the classical idiopathic Parkinson's disease in certain associated clinical features, poor response to levodopa, distinctive pathological characteristics and poor prognosis. Associated clinical features include symmetrical onset, infrequent or atypical tremor, prominent rigidity in axial musculature, bradykinesia, early postural instability, supranuclear gaze palsy, early autonomic failure, pyramidal affection, cerebellar involvement, alien limb phenomenon, apraxia and significant early cognitive dysfunction in some cases. Progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and dementia with Lewy body disease (DLB) are commoner disorders. Less frequent disorders are cortico-basal ganglionic degeneration (CBGD), frontotemporal dementia with chromosome 17 (FTDP-17), Pick's disease, parkinsonian-dementia complex of Guam, Pallidonigral degeneration, Wilson's disease and a rigid variant of Huntington's disease. During the last 3 decades, major progress has been made in understanding PSP, CBGD and FTDP-17, which are tau disorders. MSA and DLB together with idiopathic Parkinson's disease are called alpha-synucleinopathies. Recent studies show that the diagnosis of these Parkinsonism plus syndromes improves when strict diagnostic criteria are used. However, unusual presentations may pose a diagnostic challenge. The shortcomings of the current studies demand the need for further research to identify biologic markers that may allow earlier diagnosis, and understanding of the factors leading to alpha-synuclein or tau aggregation. Identification of therapeutic strategies that may prevent the aggregation of these proteins and rescue dysfunctional cells has been stressed. This review focuses on the advances in the clinical, neuroimaging, pathologic, genetic and management aspects of these disorders.
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PMID:Parkinsonism plus syndrome--a review. 1457 Sep 99

PET imaging provides the means to study neurochemical, hemodynamic, or metabolic processes that underlie movement disorders in vivo. Because the extent of presynaptic nigrostriatal dopaminergic denervation can be quantified in PD even at an early or preclinical stage of the disease, PET imaging may allow the selection of at-risk subjects for neuroprotective intervention trials. These techniques may also provide markers to follow progression of disease or evaluate the effects of neurorestorative interventions in patients who have more advanced disease. PET is expected to play an increasing role in the selection of patients who have PD for deep brain stimulation. Dopaminergic studies may have a limited clinical role in the diagnosis of patients who have symptoms that suggestive of PD yet do not respond to typical dopaminergic drugs, such as patients who have vascular parkinsonism or ET with mild resting tremor who may have normal dopaminergic innervation. The differential diagnosis between PD and multiple system atrophy, progressive supranuclear palsy, or corticobasal degeneration is not yet clearly established by PET, but combined pre- and postsynaptic dopaminergic imaging may be able to distinguish early idiopathic PD from atypical parkinsonian disorders, in general. Huntington's chorea is characterized by more prominent striatal dopamine receptor loss, whereas nigrostriatal denervation is present to a lesser degree. Patients who have TS may have enhanced synaptic dopamine release in the putamen. Functional imaging studies have generally failed to demonstrate nigrostriatal denervation in essential tremor or idiopathic dystonia. Studies have shown striatal dopamine receptor loss in selected subtypes of dystonic patients. In conclusion, it is expected that PET will help us to better understand the pathophysiology of movement disorders, increase the diagnostic accuracy, allow preclinical diagnosis, monitor disease progression, and evaluate the efficacy of therapeutic agents. Pharmacologic radioligand displacement studies and the development of new nondopaminergic ligands may further aid in the unraveling of cerebral mechanisms that underlie movement disorders.
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PMID:The role of positron emission tomography imaging in movement disorders. 1502 62

We report on a 28-year-old man who presented with right hand tremor, bradykinesia, and rigidity of his right side extremities. Our case report emphasizes that markedly asymmetrical parkinsonism can be an initial presentation of adult-onset Huntington's disease (HD), and different clinical presentations can be observed in members of an individual HD family with the same CAG repeat length.
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PMID:Markedly asymmetrical parkinsonism as a leading feature of adult-onset Huntington's disease. 1525 54

Parkinson's disease (PD) is a common neurodegenerative disorder of adulthood characterized clinically by rigidity, bradykinesia, resting tremor, and postural instability. The annual incidence of PD ranges between 16 and 19 individuals per 100,000 (Twelves et al., Mov Disord 2003;18:19-31). Historically, PD has been commonly viewed as an idiopathic or environmentally triggered condition. However, as is true with most common conditions, there have been several families reported with PD who demonstrate a classic Mendelian pattern of inheritance. To date, nine genetic loci have been reported and four pathogenic genes have been identified: alpha-synuclein, parkin, DJ1, and PINK1. Families with alterations in these genes or linked sites demonstrate either recessive or dominant inheritance patterns and may have typical and/or atypical symptoms, with an age of onset extending from the second to the sixth decade. Commercial tests for parkin and alpha-synuclein mutations are now available. We predict that physicians, particularly neurologists, increasingly will be approached for information and referrals regarding genetic testing. To assist patients and their families, physicians will not only need to know when such testing is likely to yield a meaningful result but also be aware of the possible social and emotional consequences of testing. The following is a review of what is currently known about the genetics of PD within this context. We discuss what is known about genetic testing for Huntington's disease, a well-described model for genetic testing in a neurodegenerative disorder. We explore the utility, appropriateness, and possible implications of genetic testing for diagnostic and presymptomatic purposes.
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PMID:Genetic testing in Parkinson's disease. 1550 1

Motor and phonic tics are most frequently due to Tourette syndrome, but there are many other causes of tics. We analyzed data on 155 patients with tics and co-existent disorders (101M/54F; mean age 40.5 +/- 20.2 years). Fourteen (9.0%) patients had tics associated with an insult to the basal ganglia, such as head trauma (N = 4, 2.5%), stroke (N = 2, 1.2%), encephalitis (N = 3, 1.9%) and other causes. In addition, certain drugs, toxins, and post-infectious causes were associated with tics. Rarely, peripheral injury can cause movement disorders, including tics (N = 1, 0.6%). Pervasive developmental disorders, including Asperger's syndrome (N = 13, 8.3%), mental retardation (N = 4, 2.5%), autism (N = 3, 1.9%), and Savant's syndrome (N = 1, 0.6%), also may be associated with tics, as noted in 21 of the 155 patients (13.5%). Genetic and chromosomal disorders, such as Down's syndrome 5 (3.2%), neuroacanthocytosis (N = 2, 1.2%), and Huntington's disease (N = 1, 0.6%), were associated with tics in 16 patients (10.3%). We have also examined the co-existence of tics and other movement disorders such as dystonia (N = 31, 20.0%) and essential tremor (N = 17, 10.9%). Sixteen (10.3%) patients presented psychogenic tics, and one (0.6%) psychogenic tics and dystonia; conversely, Tourette syndrome preceded the onset of psychogenic dystonia (N = 1, 0.6%), and psychogenic tremor (N = 1, 0.6%) in two patients. Finally, 12 (7.7%) patients had tics in association with non-movement related neurological disorders, such as static encephalopathy (N = 2, 1.2%) and seizures (N = 3, 1.9%). To understand the physiopathology of tics and Tourette syndrome, it is important to recognize that these may be caused or associated with other disorders.
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PMID:Secondary tics and tourettism. 1596 46

Movement disorders (ataxia, dystonic disorders, gait disorders, Huntington disease, myoclonus, parkinsonism, spasticity, tardive dyskinesia, tics and tremor) are clinically, pathologically and genetically heterogeneous and are characterized by impairment of the planning, control or execution of movement. Current classifications of these disorders have inherent shortcomings due to the complex nature of movement disorders and the lack of diagnostic tests for the majority. Undiscriminating terminology, as well as the clinical, pathological and genetic heterogeneity, further complicate the development of comprehensive categorizations. Modern classification schemes tend to focus on clinical, pathological or genetic/molecular criteria, but more recent attempts have been made to integrate across these levels. From a historical perspective, two 'golden ages' have shaped the current and evolving classification schemes: (1) the definition of clinical pathological entities in the early twentieth century and (2) the application of molecular neurogenetics in the past 10-15 years. However, the classification of movement disorders on clinical grounds (according to age at onset, distribution of symptoms, disease course, provoking factors and therapeutic response) remains one of the most useful modes of categorization. Postmortem criteria have been employed to distinguish between degenerative and nondegenerative disorders, and specific hallmarks may be required to establish or confirm a diagnosis. Genetic features used for classification purposes include mode of inheritance and molecular genetic data, such as linkage to a known gene locus or identification of a specific genetic defect. A final classification scheme is based on alterations in molecular mechanisms (e.g. trinucleotide expansions) or protein function (e.g. channelopathies). Despite recent advances, it may not be possible to develop the 'ultimate' classification of movement disorders, and different patterns of lumping and splitting may be useful for the clinician, the pathologist or the geneticist/molecular biologist. Furthermore, certain individual cases with unique features may not fit into any particular category. Continued research by both clinicians and basic scientists is necessary in order to refine and redefine classification schemes of movement disorders.
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PMID:Movement disorders: classifications. 1586 75

Complexins are presynaptic proteins that bind to the SNARE complex where they modulate neurotransmitter release. A number of studies report changes in complexins in psychiatric (schizophrenia and depression) and neurodegenerative disorders (Huntington's disease, Wernicke's encephalopathy and Parkinson's disease). Here, we characterize the behavioural phenotype of Cplx1 knockout (Cplx1-/-) mice. Cplx1-/- mice develop a strong ataxia in the absence of cerebellar degeneration. Although originally reported to die within 2-4 months after birth, when reared using an enhanced feeding regime, these mice survive normally (i.e. >2 years). Cplx1-/- mice show pronounced deficits in motor coordination and locomotion including abnormal gait, inability to run or swim, impaired rotarod performance, reduced neuromuscular strength, dystonia and resting tremor. Although the abnormal motor phenotype dominates their overt symptoms, Cplx1-/- mice also show other behavioural deficits, particularly in complex behaviours. They have deficits in grooming and rearing behaviour and show reduced exploration in several different paradigms. They also show deficits in tasks reflecting emotional reactivity. They fail to habituate to confinement and show a 'panic' response when exposed to water. The abnormalities seen in the behaviour of Cplx1-/- mice reflect those predicted from the distribution of complexin I in the brain. Our data show that complexin I is essential not only for normal motor function in mice, but also for normal performance of other complex behaviours. These results support the idea that altered expression of complexins in disease states may contribute to the symptomatology of disorders in which they are dysregulated.
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PMID:Profound ataxia in complexin I knockout mice masks a complex phenotype that includes exploratory and habituation deficits. 1600 Mar 19

The authors present a man with Huntington disease who was treated with levetiracetam (Keppra) in an effort to reduce chorea. Chorea was markedly reduced, but the patient developed parkinsonism and lethargy after 6 weeks of treatment. Symptoms consisted of resting tremor, rigidity, increased dystonia, and gait difficulty. Side effects from levetiracetam resolved completely within 7 days of levetiracetam discontinuation, and chorea returned to baseline.
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PMID:Levetiracetam-induced parkinsonism in a Huntington disease patient. 1709 92

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized behaviorally by chorea, incoordination, and shortened lifespan and neuropathologically by huntingtin inclusions and neuronal degeneration. In order to facilitate studies of pathogenesis and therapeutics, we have generated a new inducible mouse model of HD expressing full-length huntingtin (Htt) using a tetracycline-regulated promoter. In double transgenic mice Htt was expressed widely in the brain under the control of the tet-transactivator (tTA) driven by the prion promoter PrP (in the absence of doxycycline). Mice expressing full-length mutant Htt, but not full-length normal Htt, displayed a progressive behavioral phenotype, consisting of slowed and irregular voluntary movements, gait ataxia, tremor and jerky movements, incoordination, and weight loss, with a shortened lifespan. Neuropathology included prominent intranuclear inclusions in cortex and striatum as well as cytoplasmic aggregates. This phenotype is very similar to the phenotypes of previous transgenic mice expressing N-terminal fragments of mutant Htt. The current HD-transgenic mice had nuclear accumulation of Htt, particularly an approximately 60-kDa fragment, which appears to represent an N-terminal cleavage product. This fragment is smaller than calpain or caspase-derived cleavage products of Htt, but it is comparable to a product, termed cp-A, which accumulates in nuclei of cells in a previously described cell model. This new mouse model may be useful in the future for pathogenic and preclinical therapeutic studies related to HD. The data suggest that proteolytic processing could be a part of the pathogenesis of HD, potentially representing an attractive therapeutic target.
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PMID:Progressive phenotype and nuclear accumulation of an amino-terminal cleavage fragment in a transgenic mouse model with inducible expression of full-length mutant huntingtin. 1615 Jun


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