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

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) was originally found among inhabitants of the Charlevoix-Saguenay region of northeastern Quebec in Canada. This disease is a neurodegenerative disorder characterized by early-onset spastic ataxia, dysarthria, nystagmus, distal muscle wasting, finger and foot deformities, and retinal hypermyelination. The principal neuropathology comprises atrophy of the upper vermis and the loss of Purkinje cells in the cerebellum. The SACS gene was originally reported to consist of a single gigantic exon spanning 12.8 kb with an 11.5-kb open reading frame (ORF), and to encode the protein sacsin. Recently, eight exons upstream from the original gigantic one, however, have been found, and the new ORF has elongated to 13.7 kb. To date, at least 28 mutations have been found in Quebec and non-Quebec patients including ones in Italy, Japan, Spain, Tunisia, and Turkey, and ARSACS thus shows a worldwide occurrence. Although most of the mutations reported have been in the gigantic exon, the genotype is now expanding upstream from this gigantic exon. Therefore, the new exons upstream of the gigantic one should be analyzed when a case is clinically compatible with ARSACS, even without any mutation in the gigantic exon. Although Quebec patients show a homogeneous phenotype, non-Quebec patients exhibit some atypical clinical features, as follows: slightly later onset than that in Quebec patients, absence of retinal hypermyelination, intellectual impairment, and lack of spasticity. Thus, since ARSACS shows the clinical diversity, the SACS gene should be analyzed not only in typical cases as Quebec patients but also in atypical cases as non-Quebec patients. As more SACS mutations are identified worldwide, the clinical spectrum of 'sacsinopathies' will expand, and a finer genotype-phenotype correlation study will become possible and shed light on the molecular mechanism underlying ARSACS.
Cerebellum 2007
PMID:Sacsinopathies: sacsin-related ataxia. 1785 17

"Unertan syndrome" consists of two main symptoms: quadrupedal gait and primitive cognitive abilities including language and conscious experience. To assess the central mechanisms involved in this syndrome, the authors performed MRI and PET scans on affected and unaffected individuals from both families. All affected individuals were also subjected to neurological examination. To assess the integrity of the peripheral and central vestibular system, Barany's caloric test was applied to the affected individuals. Brain MRI and PET scans were performed on normal subjects (n = 7) and patients (n = 7). Right- and left-cerebral and cerebellar areas, including the vermial and callosal areas, were measured on the MRI scans using a computer cursor. Quadrupedal gait, mental retardation, dysartric speech, nystagmus, severe truncal ataxia, hyperreflexia, astasia, and abasia were observed in the affected individuals from both families. Cerebellum and vermis were atrophic in the MRI and PET scans of the first family. In contrast, the brain MRI seemed to be normal in the MRI and PET scans of affected individuals from the second family. The caloric test revealed central vestibular damage in patients from the first family and peripheral vestibular damage in patients from the second family. The results suggest that "Unertan syndrome," discovered in two unrelated families, may be caused by peripheral or central vestibular damage resulting from different genetic defects. Cerebellar hypoplasia may not be a prerequisite for the emergence of this syndrome. Primitive mental abilities may be explained by damage within the vestibulo-cerebellar system, whereas the quadrupedal gait may be due to a genetic defect within the higher brain centers that suppress the atavistic brain networks controlling quadrupedal gait and helped in the emergence of the habitual bipedal gait during human evolution. This retarded development of human locomotion - devolution - may illuminate the brain mechanisms responsible for the transition from quadrupedality to bipedality in human evolution.
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PMID:"Unertan syndrome" in two Turkish families in relation to devolution and emergence of Homo erectus: neurological examination, MRI, and PET scans. 1830 5

Sporadic spinocerebellar ataxias (SCAs) comprise heterogeneous diseases with poorly understood epidemiologies and etiologies. A population-based epidemiological analysis of sporadic ataxias in the Japanese population was described. The prevalence rate of SCAs in the Japanese population is estimated to be 18.5/100,000. Sporadic SCAs account for 67.2% of total SCAs including hereditary SCAs, with olivopontocerebellar atrophy (OPCA) being the most common form sporadic ataxia (64.7%). The natural history analysis conducted on the basis of International Cooperative Ataxia Rating Scale (ICARS) showed that only 33% of patients with OPCA were able to walk at least with one stick 4-5 years after the onset of OPCA, which is much less than that of patients with cortical cerebellar atrophy (CCA). Similarly, 43% of patients with OPCA were able to stand alone 4-5 years after the onset, while 76% of patients with CCA were able to stand alone at the same disease duration. A population-based epidemiological analysis should provide essential information on the natural history of SCAs.
Cerebellum 2008
PMID:Sporadic ataxias in Japan--a population-based epidemiological study. 1841 74

The spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal dominantly inherited progressive ataxia diseases. Up to now, almost 30 different gene loci have been found. In 14 of them, the underlying mutations have been identified. The more common SCAs, SCA1, 2, 3 and 6 are due to translated CAG repeat expansions that code for an elongated polyglutamine tract within the respective proteins. These diseases belong to a larger group of polyglutamine disorders that also includes Huntington's disease. Epidemiological studies conducted in different European regions found prevalence rates of SCAs ranging from 0.9 to 3.0:100,000. In all SCAs, ataxia is the prominent symptom. However, the majority have a complex phenotype in which ataxia is accompanied by varying non-ataxia symptoms. In all ataxia patients with proven or suspected autosomal dominant mode of inheritance, the available molecular genetic tests for SCA mutations should be performed. Depending on the geographical origin of the family, these tests will lead to positive diagnostic results in at least half of the families.
Cerebellum 2008
PMID:The clinical diagnosis of autosomal dominant spinocerebellar ataxias. 1841 79

Spinocerebellar ataxia 21 is a slowly progressive and mild ataxia associated with extrapyramidal signs. Affected subjects exhibit a moderate gait and limb ataxia variably associated with akinesia, tremor, rigidity, hyporeflexia, and mild cognitive impairment. The responsible gene has been assigned to a 19 Mbases interval on chromosome 7p in a single French family. No evidence of significant linkage to this locus was found in 21 other families obtained from the EUROSCA consortium. The locus interval contains several candidate genes that could be responsible for the disease. Direct sequencing of NDUFA4, PHF14, KIAA0960, ARLA4, ETV1, DGKB, HDAC9, FERD3L, ITGB8, and SP4 genes were performed, but all the direct mutation analyses were negative excluding pathogenic mutations associated with the disease. Therefore, the gene responsible for SCA21 remains to be identified.
Cerebellum 2008
PMID:Slowly progressive spinocerebellar ataxia with extrapyramidal signs and mild cognitive impairment (SCA21). 1841 88

Spinocerebellar ataxia type 8 (SCA8) is a dominantly inherited, slowly progressive neurodegenerative disorder caused by a CTG.CAG repeat expansion located on chromosome 13q21. The expansion mutation was isolated directly from the DNA of a single patient using RAPID cloning and subsequently shown to co-segregate with disease in additional ataxia families including a seven-generation kindred (the MN-A family). The size-dependent penetrance of the repeat found in the large MN-A kindred makes it appear as though some parts of the family have a dominant disorder while other parts of this same family have recessive or sporadic forms of ataxia. While the linkage and size-dependent penetrance of the SCA8 CTG.CAG expansion in the MN-A family argue that the SCA8 expansion causes ataxia, the reduced penetrance in other SCA8 families and the discovery of expansions in the general population have led to a controversy surrounding whether or not the SCA8 expansion is pathogenic. A recently reported mouse model in which SCA8 BAC-expansion but not BAC-control lines develop a progressive neurological phenotype now demonstrates the pathogenicity of the (CTG.CAG)(n) expansion. These mice show a loss of cerebellar GABAergic inhibition and, similar to human patients, have 1C2-positive intranuclear inclusions in Purkinje cells and other neurons. Additional studies demonstrate that the SCA8 expansion is expressed in both directions (CUG and CAG) and that a novel gene expressed in the CAG direction encodes a pure polyglutamine expansion protein (ataxin 8, ATXN8). Moreover, the expression of non-coding (CUG)(n) expansion transcripts (ataxin 8 opposite strand, ATXN8OS) and the discovery of intranuclear polyglutamine inclusions suggest SCA8 pathogenesis may involve toxic gain-of-function mechanisms at both the protein and RNA levels. Our data, combined with the recently reported antisense transcripts spanning the DM1 repeat expansion in the CAG direction and the growing number of reports of antisense transcripts expressed throughout the mammalian genome, raises the possibility that bidirectional expression across pathogenic microsatellite expansions may occur in other expansion disorders, and that potential pathogenic effects of mutations expressed from both strands should be considered.
Cerebellum 2008
PMID:Bidirectional expression of the SCA8 expansion mutation: one mutation, two genes. 1841 92

Gonadotropin-releasing hormone (GnRH) is a decapeptide hypothalamic hormone that was named according to its first discovered function--at the head of the neuroendocrine reproductive axis. Numerous other organ systems express GnRH and/or its receptor, although a specific physiological role for GnRH outside of the reproductive axis has yet to be established. Several studies in lower vertebrates have reported GnRH and/or its receptor in the cerebellum. Here, we describe the presence of immunoreactive GnRH receptors in the Purkinje cells of the mammalian cerebellum for the first time. This study provides compelling anatomical evidence for a common link between the cerebellum and the hypothalamo-pituitary axis. Dysfunction of this link occurs in the rare genetic ataxia disorders--Gordon Holmes syndrome and Boucher-Neuhauser syndrome.
Cerebellum 2008
PMID:The gonadotropin-releasing hormone type I receptor is expressed in the mouse cerebellum. 1859 35

We have recently mapped the spinocerebellar ataxia type 28 (SCA28) locus on chromosome 18p11.22 in a four-generation Italian family. The clinical phenotype in affected individuals of this family was characterized by juvenile onset, slowly progressive gait and limb ataxia, dysarthria, hyperreflexia at lower limbs, nystagmus, and ophthalmoparesis. The mean age at onset was 19.5 years, and no evidence of anticipation between generations was observed. The disease locus on chromosome 18p11.22-q11.2 was found to span a region of 7.9 Mb of genomic DNA. Direct sequencing of candidate genes within the critical interval led to the identification of a heterozygous point mutation in one of them. The mutation was located in a highly conserved domain with proposed functional properties in the protein product of the SCA28 gene, and segregated with the disease phenotype in all affected members of this family. Thereafter we have screened 105 patients with autosomal dominant spinocerebellar ataxia who had resulted negative for mutations in known SCA genes. Genetic screening allowed the identification in a second Italian family of a distinct missense mutation located in the very same functional domain of the protein. The affected members of this second family exhibited a neurological phenotype similar to that of the original family. Both mutations, not found in more than 500 chromosomes, are associated with amino acid changes (Glu-->Lys and Ser-->Leu, respectively) in evolutionarily conserved residues of the alleged SCA28 gene. Our data point to a putative pathogenic role of these mutations, and indicate SCA28 as the sixth recognized SCA genotype caused by point mutations.
Cerebellum 2008
PMID:Spinocerebellar ataxia type 28: a novel autosomal dominant cerebellar ataxia characterized by slow progression and ophthalmoparesis. 1876 91

Gluten ataxia is an immune-mediated disease triggered by the ingestion of gluten in genetically susceptible individuals. It should be considered in the differential diagnosis of all patients with idiopathic sporadic ataxia. Early diagnosis and treatment with a gluten free diet can improve ataxia and prevent its progression. Readily available and sensitive markers of gluten ataxia include antigliadin antibodies. IgA deposits against TG2 in the small bowel and at extraintestinal sites are proving to be additional reliable and perhaps more specific markers of the whole spectrum of gluten sensitivity. They may also hold the key to its pathogenesis.
Cerebellum 2008
PMID:Gluten ataxia. 1878 12

16q22.1-linked autosomal dominant cerebellar ataxia (16q-ADCA) is a recently defined subtype of ADCA identified by a disease-specific C/T substitution in the 5' untranslated region of the puratrophin-1 gene. In Nagano, the central mountainous district of the main island of Japan, 16q-ADCA and spinocerebellar ataxia type 6 (SCA6) are the most and second most prevalent subtypes of ADCA, respectively. Both subtypes are classified into Harding's ADCA III, but little attention has been given to the differences in the severity and progression rate of cerebellar ataxia between 16q-ADCA and SCA6. We investigated the clinical severity and progression rate of cerebellar ataxia of 16q-ADCA patients using international cooperative ataxia rating scale and scale for the assessment and rating of ataxia and compared them with those of SCA6 patients. The age at onset was much higher in 16q-ADCA patients (60.1 +/- 9.8 years, n = 66) than in SCA6 patients (41.1 +/- 8.7 years, n = 35). Clinical features of 16q-ADCA were basically consistent with pure cerebellar ataxia, as well as in SCA6, but gaze-evoked nystagmus was observed less frequently in 16q-ADCA patients than in SCA6 patients. When compared at almost the same disease duration after onset, the severity of cerebellar ataxia was a little higher, and the progression rate seemed more rapid in 16q-ADCA patients than in SCA6 patients, but the differences were not significant.
Cerebellum 2009 Mar
PMID:Severity and progression rate of cerebellar ataxia in 16q-linked autosomal dominant cerebellar ataxia (16q-ADCA) in the endemic Nagano Area of Japan. 1885 94


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