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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carriers of premutation within the FMR1 gene are typically normal intellectually, although a limited number of them have been reported to have either learning disabilities or mild dysmorphic features. A neurological condition involving intention tremor, ataxia and cognitive decline has recently been identified among older males carrying premutation alleles of the FMR1 gene, including grandfathers of children affected with fragile X syndrome. Characteristic findings from magnetic resonance imaging include cerebral and cerebellar volume loss and altered signal intensities of the middle cerebellar peduncles. This syndrome may represent one of the more common causes of tremor, ataxia and dementia among older males. The diagnosis of FXTAS is straightforward if a family at high genetic risk could be identified. Thus genetic counseling should be offered to such family.
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PMID:[Fragile X-associated tremor/ataxia syndrome]. 1598 Nov 62

These recommendations describe the minimum standard criteria for genetic counseling and testing of individuals and families with fragile X syndrome, as well as carriers and potential carriers of a fragile X mutation. The original guidelines (published in 2000) have been revised, replacing a stratified pre- and full mutation model of fragile X syndrome with one based on a continuum of gene effects across the full spectrum of FMR1 CGG trinucleotide repeat expansion. This document reviews the molecular genetics of fragile X syndrome, clinical phenotype (including the spectrum of premature ovarian failure and fragile X-associated tremor-ataxia syndrome), indications for genetic testing and interpretation of results, risks of transmission, family planning options, psychosocial issues, and references for professional and patient resources. These recommendations are the opinions of a multicenter working group of genetic counselors with expertise in fragile X syndrome genetic counseling, and they are based on clinical experience, review of pertinent English language articles, and reports of expert committees. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a health care provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.
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PMID:Genetic counseling for fragile x syndrome: updated recommendations of the national society of genetic counselors. 1604 89

Some carriers of a "premutation" allele of the FMR1 gene develop late-onset tremor/ataxia. We conducted a magnetic resonance imaging volumetric study in an unselected sample of eight older male premutation carriers. Volumetric measures, including total brain volume, and the volumes of cerebrum, cerebellum, and cerebral cortex all were significantly reduced in premutation carriers compared with similar data from 21 age-matched normal controls. Total brain and cerebral volumes were significantly related to the number of CGG repeats in the FMR1 gene. Moreover, increased hippocampal volume indicates this premutation may account for both neurodegenerative and neurodevelopmental changes.
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PMID:Magnetic resonance imaging study in older fragile X premutation male carriers. 1604 24

Late onset cerebellar ataxia can be caused by several genetic mutations but a large percentage of patients remain undiagnosed. Thirty-eight patients with onset of slowly progressive, pure cerebellar ataxia >or=40 years-of-age were identified from a large ataxia database. Their clinical findings and quantitative oculomotor tests were reviewed; all were screened for SCA1, SCA2, SCA3, SCA6, SCA8, SCA14, and the Fragile X premutation (FMR1). All 47 exons of CACNA1A were screened for mutations. Genetic analysis uncovered a mutation in 11 patients. The SCA6 mutation was present in 8 patients (repeats 22-23). Three additional genetic mutations were found: SCA1 (42 repeats), SCA3 (66 repeats), and SCA8 (121 repeats). Patients without identified genetic mutations were characterized by 1) a later age of onset, 2) truncal without extremity ataxia, 3) and down beat nystagmus. Although only a third of these idiopathic late onset ataxia patients had a positive family history, this homogeneous syndrome probably represents a yet to be identified genetic disorder.
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PMID:Late-onset pure cerebellar ataxia: differentiating those with and without identifiable mutations. 1610 27

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a progressive adult-onset tremor/ataxia syndrome caused by premutations in the FMR1 gene. In cranial MRI, the most characteristic findings are bilateral T2 hyperintense lesions within the middle cerebellar peduncles. Here we present a sibpair of two affected brothers presenting with very different symptoms (typical FXTAS versus essential tremor-like), disease progression, and MRI findings, illustrating broad intrafamilial variability of FXTAS. Also, their family history suggests further evidence of possible manifestation of FXTAS in women.
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PMID:Intrafamilial variability in fragile X-associated tremor/ataxia syndrome. 1612 12

The FMR1 gene is involved in two different syndromes: Fragile X syndrome and Fragile X-associated tremor/ataxia syndrome (FXTAS). Fragile X syndrome is a childhood disease and is associated with mental retardation as the main clinical characteristic, whereas FXTAS develops in men and women over 50 years of age. FXTAS represents a new form of inclusion disorder with a high prevalence in the general population. The neurologic phenotype of FXTAS includes intention tremor and ataxia. Associated features are dementia, parkinsonism, neuropathy, and autonomic dysfunction. Elevated FMR1 transcripts have been proposed as the molecular basis of the pathogenic mechanism leading to FXTAS. This review discusses recent developments in the clinical phenotype, prevalence and screening, animal models, and molecular mechanisms of RNA-based pathogenesis in FXTAS.
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PMID:FXTAS: a progressive neurologic syndrome associated with Fragile X premutation. 1613 24

A 75-year-old man had progressive difficulty with walking, intention tremor, ataxia, and mild cognitive deficits. MRI scan ofthe brain showed symmetrical hyperintensities in the middle cerebellar peduncles. DNA analysis ofthe fragile-X gene revealed an expansion of 150-200 repetitions in the FMR1-gene, compatible with a premutation in the fragile-X gene. Two years later, after progression of the symptoms, the patient was admitted to a nursing home. The clinical picture of intention tremor, parkinsonism and ataxia with white matter lesions and atrophy on MRI occurs in carriers of this premutation and has recently been described as the fragile-X-associated tremor/ataxia syndrome. Recognition of this clinical picture is important for the patient but also for the relatives, since female carriers of the premutation have an increased risk of offspring with the fragile-X syndrome.
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PMID:[Progressive ataxia and cognitive deficits caused by premutation in the fragile-X-mental retardation gene]. 1627 33

The Swedish Medical Society's Delegation for Medical Ethics held in October 2004 a workshop on the new ethical implications on genetic counselling in families where a premutation or mutation in the FMR1 gene was found. New research has revealed that premutation carrier women have an increased risk of premature ovarian failure, and, thus, their fertile sisters may be mutation carriers with an increased risk of having a child with the fragile X syndrome. Premutation carrier males have after the age of 50 an increased risk of developing ataxia and cognitive dysfunctions. Accordingly, their daughters have a high risk of having a child with the fragile X syndrome. The ethical aspects of these issues were discussed at the workshop with suggestions on the way forward.
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PMID:[New discoveries about the fragile X syndrome complicate genetic counseling. More symptoms than earlier known caused by the disease gene]. 1632 54

We reviewed prevalence rates of fragile X mental retardation gene (FMR1) repeat expansions in movement disorder populations. Inclusion criteria included published epidemiological studies from systematic searches of Medline, Pubmed, Cochrane Databases and Web Science. Thirteen cross-sectional studies were carried out between 2003 and 2005. Subjects with ataxia showed higher than expected rates while those with essential tremor and parkinsonism showed lower rates. The heterogeneous design of the studies, inclusion criteria and mean age of subjects may have led to underestimation of FMR1 repeat expansion prevalence rates.
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PMID:Prevalence of FMR1 repeat expansions in movement disorders. A systematic review. 1649 2

Disorders associated with fragile X syndrome involve a trinucleotide (CGG) repeat expansion in the FMR1 gene. Recently, a progressive movement disorder (fragile X-associated tremor/ataxia syndrome [FXTAS]) has been identified in premutation carriers, persons with 55 to 200 CGG repeats. In addition to ataxia, action tremor, and Parkinsonism, early case reports suggested that FXTAS involves impaired cognition, but the precise nature of the impairment has not been elucidated. In this first, preliminary study of the subject, circumscribed aspects of cognitive functioning were examined in 25 men with FXTAS. Subjects' performance on the cognitive tests was compared with normative data. Scores on two measures of executive cognitive functioning showed a high prevalence of substantial impairment. Capacity for inhibition was severely affected in one-quarter of this highly educated sample; information processing speed was profoundly impaired in most subjects. Although mean verbal and performance IQ scores were not significantly different from the general population, they were quite low given the sample's educational level. Cognitive and functional impairment was greater for men with more CGG repeats, although number of repeats was not associated with age of onset of either tremor or ataxia. The results provide evidence that FXTAS involves marked impairment of executive cognitive abilities.
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PMID:Impairment in the cognitive functioning of men with fragile X-associated tremor/ataxia syndrome (FXTAS). 1678 Aug 89


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