Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multiple system atrophy (MSA) is a neurodegenerative disorder of unknown cause. The only case-control study conducted in MSA patients to date suggested a possible contributory genetic component in the pathogenesis of this disorder. The aim of this study was to evaluate a possible overlap between clinically or pathologically well-defined MSA and other conditions with an identified genetic defect causing spinocerebellar degeneration in humans or mutant mice strains. The spinocerebellar ataxia type 1 and 3 genes (SCA1 and SCA3) were analyzed for a pathologic expansion in 80 patients with MSA to evaluate a possible overlap between MSA and SCA1 or SCA3. Weaver mice and lurcher mice are animal models for spinocerebellar degeneration; both share pathologic features with MSA. We sequenced the H5 pore region of the human homologue of the weaver mouse gene, hiGIRK2, in all our patients. In lurcher mice, previous biochemical studies have shown a decreased intracellular response to insulin-like growth factor 1 (IGF-1) in the cerebellar cortex, and we thus investigated the possibility of an allelic association between MSA and the receptor for IGF-1. In addition, we evaluated a possible involvement of the ciliary neurotrophic factor gene (CNTF) and examined the role of HLA-A32 to clarify the conflicting data from previous studies. No changes were detected in any of the analyzed genes. Our studies strongly suggest that MSA is an autonomous syndrome distinct from identified genetic causes for spinocerebellar degeneration.
 ...
PMID:Multiple-system atrophy is genetically distinct from identified inherited causes of spinocerebellar degeneration. 940 53

Forty-one patients suffering from autosomal dominant cerebellar ataxia type I (ADCA-I) were subjected to a genotype-phenotype correlation analysis using molecular genetic assignment to the spinocerebellar ataxia type 1, 2 or 3 (SCA1, -2 or -3) genetic locus, clinical examination and nerve conduction as well as evoked potential studies. Pyramidal tract signs, pale discs, and dysphagia were more frequent in SCA1 compared with SCA2 and SCA3 patients, while double vision occurred less frequently. Visual evoked potentials and motor evoked potentials following transcranial magnetic stimulation were abnormal in almost all SCA1 patients, but only in a minority of SCA2 and SCA3 patients. In contrast, somatosensory evoked potentials were delayed or absent in the majority of patients with no significant differences between the mutations. Abnormalities of brainstem auditory evoked potentials were found in about half of the patients irrespective of the underlying mutation. In addition, reduced sensory nerve action potentials, suggesting sensory axonal neuropathy were found in all three mutations. These findings provide electrophysiological evidence that pyramidal and visual pathways are differentially affected in SCA1, SCA2 and SCA3 patients.
 ...
PMID:Autosomal dominant cerebellar ataxia type I. Nerve conduction and evoked potential studies in families with SCA1, SCA2 and SCA3. 944 69

An expanded and unstable CAG repeat in the coding region of the MJD1 gene is the mutation responsible for spinocerebellar ataxia 3/Machado-Joseph disease. In order to determine whether there was a higher degree of instability in affected regions, the size of the expanded CAG repeat was analyzed in different regions of the central nervous system, in two unrelated SCA3/MJD patients. The degree of somatic mosaicism was quantified and compared to that in a SCA1 patient. Instability of the expanded CAG repeat was observed in peripheral tissues as well as in CNS of the three patients, but there was no correlation between the degree of mosaicism and the selective vulnerability of CNS structures. As in the other diseases caused by expanded CAG repeats, a lower degree of mosaicism was found in the cerebellar cortex of both SCA1 and SCA3/MJD patients, probably reflecting specific properties of this structure. In SCA3/MJD, the degree of mosaicism seemed to correlate with age at death rather than with the size of the expanded CAG repeat. Finally, somatic instability was more pronounced in SCA1 than in SCA3/MJD patients.
 ...
PMID:Somatic mosaicism of the CAG repeat expansion in spinocerebellar ataxia type 3/Machado-Joseph disease. 945 Aug 99

We report here a simple method for generating large CAG/CTG repeat sequences. We have applied this method to clone the genomic sequence containing the CAG/CTG repeat and its upstream intronic sequence present in spinocerebellar ataxia type 3 or Machado-Joseph disease (SCA3/MJD) by a modified DIRECT method. With these modifications we have considerably simplified the generation of the repeat probe used to screen for anomalous bands. This method will facilitate the molecular approach to other genetic disorders where expansions of repeat sequences could be involved.
 ...
PMID:Large CAG/CTG repeat templates produced by PCR, usefulness for the DIRECT method of cloning genes with CAG/CTG repeat expansions. 946 48

In some neurodegenerative diseases, genetic anticipation correlates with expansions of the CAG/CTG repeat sequence above the normal range through the generations of a pedigree. Among these neurodegenerative diseases are late onset autosomal dominant cerebellar ataxias (ADCA). ADCA are genetically heterogeneous disorders with different cloned genes for spinocerebellar ataxia type 1 (SCA1), type 2 (SCA2), type 3 or Machado-Joseph disease (SCA3/MJD), and type 6 (SCA6). Another related dominant ataxia, dentatorubral-pallidoluysian atrophy (DRPLA), also shows CAG/CTG repeat expansions. Genetic anticipation has been reported for all of them except for the recently cloned SCA6 gene. Other, as yet undetected SCA genes may show the same features. We have used the repeat expansion detection (RED) method to detect repeat expansions directly in DNA samples from ADCA patients not resulting from known genes. Our sample consists of 19 affected index cases, corresponding to 52.8% of our ADCA families without CAG/CTG repeat expansions in the SCA1, SCA2, SCA3/MJD, SCA6, or DRPLA genes. Eighty-nine percent of the index cases had expansions of a CAG/CTG sequence greater than 40 repeats by RED, while these were observed in only 26.9% of 78 healthy subjects from the general population (p < 0.0001). The distribution of RED fragments in controls and ADCA patients also shows significant differences with the Mann-Whitney U test (U = 376.5, p = 0.0007). Moreover, there was a significant inverse correlation between the size of expansion and the age of onset (r = -0.54, p = 0.018). These results show CAG/CTG repeat expansions of over 40 repeats in our sample of ADCA families not resulting from known SCA genes.
 ...
PMID:Uncloned expanded CAG/CTG repeat sequences in autosomal dominant cerebellar ataxia (ADCA) detected by the repeat expansion detection (RED) method. 950 87

Using a molecular diagnostic approach, we investigated 101 kindreds with autosomal dominant cerebellar ataxias (ADCAs) from the central Honshu island of Japan, including spinocerebellar ataxia type 1 (SCA1), spinocerebellar ataxia type 2 (SCA2), Machado-Joseph disease (MJD), dentatorubral and pallidoluysian atrophy (DRPLA) and spinocerebellar ataxia type 6 (SCA6). In our unselected series, MJD was the most common type of ADCA, accounting for 33.7% followed by DRPLA (19.8%), SCA2 (5.9%) and SCA6 (5.9%). No SCA1 mutations were identified. We analysed the clinical features of six molecular confirmed SCA6 kindreds: in each family, there was an expanded allele in the alpha1A-voltage dependent calcium channel comprising between 23 and 25 CAG repeats. The mean age at onset of symptoms was 43+/-13 years. The clinical features consisted predominantly of cerebellar ataxia, dysarthria and horizontal nystagmus, which was generally consistent with ADCA type 3. However several new clinical features were found in some patients: dramatic anticipation, rapid disease progression, severe ataxia associated with action tremor or action myoclonus, and very early onset, which are not described as the classical features of ADCA type 3.
 ...
PMID:Frequency analysis of autosomal dominant cerebellar ataxias in Japanese patients and clinical characterization of spinocerebellar ataxia type 6. 955 Mar 56

The aim of the present study was (i) to compare disease progression and survival in different types of degenerative ataxia, and (ii) to identify variables that may modify the rate of disease progression. We included patients suffering from Friedreich's ataxia (FRDA, n = 83), early onset cerebellar ataxia (EOCA, n = 30), autosomal dominant cerebellar ataxia (ADCA) type I (ADCA-I, n = 273), ADCA-III (n = 13) and multiple system atrophy (MSA, n = 67). Molecular genetic testing allowed us to assign 202 ADCA-I patients to one of the following subgroups: spinocerebellar ataxia type I (SCAI, n = 36), SCA2 (n = 56) and SCA3 (n = 110). To assess disease progression we defined the following disease stages: stage 0 = no gait difficulties; stage 1 = disease onset, as defined by onset of gait difficulties; stage 2 = loss of independent gait; stage 3 = confinement to wheelchair; stage 4 = death. Disease progression was most rapid in MSA, intermediate in FRDA, ADCA-I and ADCA-III and slowest in EOCA. The rate of progression was similar in SCA1, SCA2 and SCA3. The CAG repeat length was a significant risk factor for faster progression in SCA2 and SCA3, but not in SCA1. In FRDA, the time until confinement to wheelchair was shorter in patients with earlier disease onset, suggesting that patients with long GAA repeats and early disease onset have a poor prognosis. Female gender increased the risk of becoming dependent on walking aids or a wheelchair, but it did not influence survival in FRDA, SCA3 and MSA. In SCA2, female gender was associated with shortened survival. In MSA, later age of onset increased the risk of rapid progression and death.
 ...
PMID:The natural history of degenerative ataxia: a retrospective study in 466 patients. 957 87

Machado-Joseph disease (MJD) is an autosomal dominantly inherited neurodegenerative disorder characterized by varying age of onset and pronounced phenotypic heterogeneity. The clinical core features include gait ataxia, external ophthalmoplegia, nystagmus, and bulging eyes. Recently, Kawagushi et al. (1994) cloned the MJD1 gene on chromosome 14 and MJD turned out to be the fifth neurodegenerative disease caused by an unstable CAG repeat expansion. We have studied two large Danish families and one Norwegian family with MJD. Three features not previously associated with MJD are reported: dementia, generalized muscle and joint pain, and in one case neuropathological examination revealed atrophy of the inferior olives. We found a significant inverse correlation between age of onset and the length of the CAG repeat expansion, and anticipation is described through four succeeding generations. Instability of the CAG repeat expansion was most pronounced at paternal transmission.
 ...
PMID:Machado-Joseph disease in three Scandinavian families. 958 50

We analyzed 13 patients with spinocerebellar ataxia type 2 (SCA2) in seven unrelated families who live in Gunma Prefecture, Japan (population approx. 2,000,000), and documented the clinical and molecular properties correlated with the CAG repeat expansion. Twelve of the 13 patients and one presymptomatic female were genetically examined, and the CAG repeat number of the expanded and normal alleles was 40.8+/-4.8 (mean+/-S.D., n=13) and 22+/-0 (n=13), respectively. The repeat size of the expanded alleles was inversely correlated with the patients' age at onset. Paternal anticipation was observed, accompanied by an increase of the CAG repeat size. The patients presented here were clinically characterized by a relatively higher frequency of slow saccades, hyporeflexia, hypotonia, and tremor. A number of peaks in the expanded allele on polyacrylamide gel electrophoresis showed the presence of cell mosaicism in SCA2 as well. In Gunma Prefecture, SCA2, Machado-Joseph disease and spinocerebellar ataxia type 6 are almost equally present and at higher frequencies than spinocerebellar ataxia type 1 and hereditary dentatorubropallidoluysian atrophy, which are rare. Thus, the difference of frequency of autosomal dominant spinocerebellar ataxias may be present in Japan.
 ...
PMID:Analysis of spinocerebellar ataxia type 2 in Gunma Prefecture in Japan: CAG trinucleotide expansion and clinical characteristics. 958 55

The spinocerebellar ataxias (SCAs) are clinically and genetically a heterogeneous group of neurodegenerative disorders. To date, eight different loci causing SCA have been identified: SCA1, SCA2, Machado-Joseph disease (MJD)/SCA3, SCA4, SCA5, SCA6, SCA7, and dentatorubropallidoluysian atrophy (DRPLA). Expansion of a CAG repeat in the disease genes has been found in five of these disorders. To estimate the relative frequencies of the SCA1, DRPLA, MJD, SCA2, and SCA6 mutations among Portuguese ataxia patients, we collected DNA samples from 48 ataxia families and performed polymerase chain reaction (PCR) amplification of the CAG repeat mutations on chromosomes 6p, 12p, 14q, 12q, and 19p, respectively. Fifty-five individuals belonging to 34 dominant families (74%) had an expanded CAG repeat at the MJD gene. In five individuals from two kindreds with a dominant pattern of inheritance (4%), an expanded CAG repeat at the SCA2 gene was found. In MJD patients, the normal allele size ranged from 13 to 41, whereas the mutant alleles contained 65 to 80 repeats. For the SCA2 patients, normal alleles had 22 or 23, while expanded alleles had between 36 and 47 CAG units. We did not find the SCA1, DRPLA, or SCA6 mutations in our group of families. The MJD mutation remains the most common cause of SCA in Portugal, while a small number of cases are caused by mutations at the SCA2 gene, and 22% are due to still unidentified genes.
 ...
PMID:Analysis of SCA1, DRPLA, MJD, SCA2, and SCA6 CAG repeats in 48 Portuguese ataxia families. 961 52


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>