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)

The number of patients with spinocerebellar degeneration (SCD) has recently exceeds 20,000 in Japan. Among them, sporadic form is the most common form (67.2%). Among the hereditary forms of SCD, autosomal dominant (AD) form comprises 27.0%, while autosomal recessive (AR) form is rare (1.8%). Because of the rare occurrence of AR-SCD, the molecular genetic studies have been difficult to conduct. Recent progresses in molecular genetics, however, have enabled identification of causative genes for the majority of AR-SCD. Although Friedreich's ataxia is the most representative form of AR-SCD, patients with molecular diagnosis of Friedreich's ataxia have not been described in the Japanese population. Among the various forms of AR-SCD, early-onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH) seems to be the most common form in the Japanese population. Aprataxin, the causative gene for EAOH, has been suggested to play a role in the single strand DNA break repair. Interestingly, abnormalities in DNA break repair processes have been implicated in several forms of AR-SCD including AOA2, SCAN1 and ataxia telangiectasia. In this group of AR-SCD, cerebellar atrophy is more marked compared to that observed in Friedreich's ataxia. Taken together, abnormalities in DNA break repair processes may play an essential role in cerebellar degeneration in this group of AR-SCD.
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PMID:[Clinical features and molecular genetics of autosomal recessive spinocerebellar degenerations]. 1565 Dec 91

Autosomal recessive cerebellar ataxias (ARCAs) are a phenotypically and genetically heterogeneous group of diseases. Recently, a subgroup of ARCA associated with oculomotor apraxia (AOA) has been delineated. It includes at least four distinct genetic entities: ataxia-telangiectasia, ataxia-telangiectasia-like disorder, and ataxia with oculomotor apraxia type 1 (AOA1) and type 2 (AOA2). The phenotypes share several similarities, and the responsible genes, ATM, MRE11, APTX, and SETX, respectively, are all implicated in DNA break repair. As in many other DNA repair deficiencies, neurodegeneration is a hallmark of these diseases. Recently, the genes for two new autosomal recessive cerebellar ataxias with oculomotor apraxia, AOA1 and AOA2, were identified. Here, we report the phenotypic characteristics, genetic characteristics, and the recent advances concerning AOA1 and AOA2.
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PMID:New autosomal recessive cerebellar ataxias with oculomotor apraxia. 1613 25

A severe recessive cerebellar ataxia, Ataxia-Oculomotor Apraxia 2 (AOA2) and a juvenile onset form of dominant amyotrophic lateral sclerosis (ALS4) result from mutations of the Senataxin (SETX) gene. To begin characterization this disease protein, we developed a specific antibody to the DNA/RNA helicase domain of SETX. In murine brain, SETX concentrates in several regions, including cerebellum, hippocampus and olfactory bulb with a general neuronal expression profile, colocalizing with NeuN. In cultured cells, we found that SETX was cytoplasmically diffuse, but in the nucleus, SETX was punctate, colocalizing with fibrillarin, a marker of the nucleolus. In differentiated non-cycling cells, nuclear SETX was not restricted to the nucleolus but was diffuse within the nucleoplasm, suggesting cell-cycle-dependent localization. SETX missense mutations cluster within the N-terminus and helicase domains. Flag tagging at the N-terminus caused protein mislocation to the nucleoplasm and failure to export to the cytoplasm, suggesting that the N-terminus may be essential for correct SETX localization. We report here the first characterization of SETX protein, which may provide future insights into a new mechanism leading to neuron death.
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PMID:Senataxin, the yeast Sen1p orthologue: characterization of a unique protein in which recessive mutations cause ataxia and dominant mutations cause motor neuron disease. 1664 29

A subgroup of autosomal recessive cerebellar ataxias (ARCAs) associated with oculomotor apraxia (OMA) and other variable features has been reported. Ataxia-oculomotor apraxia types 1 and 2 (AOA1 and AOA2) belong to this subgroup and have been described in adults with early onset cerebellar ataxia. AOA1 is associated with oculomotor apraxia, severe sensorimotor neuropathy, choreiform movements, cognitive impairment, and cerebellar atrophy at an early age. We describe a male child with AOA1 who is homozygous for the G837A (W279X) mutation in the APTX gene. He presented at the age of 3 years 6 months with some atypical features including absence of OMA, chorea, and cerebellar atrophy. These manifestations, in addition to peripheral neuropathy, appeared at 8 years of age. We highlight the importance of considering the diagnosis of AOA1 in children with early-onset cerebellar ataxia, once other well-known disorders such as Friedreich's ataxia and ataxia-telangiectasia have been excluded.
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PMID:Atypical presentation of ataxia-oculomotor apraxia type 1. 1670 Sep 49

Mutations in the Senataxin gene (SETX) are associated with autosomal recessive ataxia-ocular apraxia 2 (AOA2) and autosomal dominant juvenile ALS (ALS4). Here, the authors describe novel homozygous missense mutations in SETX, M274I, and R1294C, found in two siblings with ataxia, peripheral neuropathy, and increased serum alpha-fetoprotein level and three other siblings with heterozygous missense mutations who were neurologically asymptomatic. The results demonstrate that the double missense mutations are responsible for AOA2 but not for ALS4.
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PMID:Autosomal recessive ataxia with peripheral neuropathy and elevated AFP: novel mutations in SETX. 1671 25

Senataxin mutations are the molecular basis of two distinct syndromes: (1) ataxia oculomotor apraxia type 2 (AOA2) and (2) juvenile amyotrophic lateral sclerosis 4 (ALS4). The authors describe clinical and molecular genetic studies of mother and daughter who display symptoms of cerebellar ataxia/atrophy, oculomotor defects, and tremor. Both patients share Senataxin mutations N603D and Q653K in cis (N603D-Q653K), adjacent to an N-terminal domain thought to function in protein-protein interaction. The N-terminal and helicase domains appear to harbor missense mutation clusters associated with AOA2 and ALS4. Working synergistically, the N603D-Q653K mutations may confer a partial dominant negative effect, acting on the senataxin N-terminal, further expanding the phenotypic spectrum associated with Senataxin mutations.
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PMID:In cis autosomal dominant mutation of Senataxin associated with tremor/ataxia syndrome. 1709 68

Autosomal recessive cerebellar ataxias (ARCA) are a heterogeneous group of rare neurological disorders involving both central and peripheral nervous system, and in some case other systems and organs, and characterized by degeneration or abnormal development of cerebellum and spinal cord, autosomal recessive inheritance and, in most cases, early onset occurring before the age of 20 years. This group encompasses a large number of rare diseases, the most frequent in Caucasian population being Friedreich ataxia (estimated prevalence 2-4/100,000), ataxia-telangiectasia (1-2.5/100,000) and early onset cerebellar ataxia with retained tendon reflexes (1/100,000). Other forms ARCA are much less common. Based on clinicogenetic criteria, five main types ARCA can be distinguished: congenital ataxias (developmental disorder), ataxias associated with metabolic disorders, ataxias with a DNA repair defect, degenerative ataxias, and ataxia associated with other features. These diseases are due to mutations in specific genes, some of which have been identified, such as frataxin in Friedreich ataxia, alpha-tocopherol transfer protein in ataxia with vitamin E deficiency (AVED), aprataxin in ataxia with oculomotor apraxia (AOA1), and senataxin in ataxia with oculomotor apraxia (AOA2). Clinical diagnosis is confirmed by ancillary tests such as neuroimaging (magnetic resonance imaging, scanning), electrophysiological examination, and mutation analysis when the causative gene is identified. Correct clinical and genetic diagnosis is important for appropriate genetic counseling and prognosis and, in some instances, pharmacological treatment. Due to autosomal recessive inheritance, previous familial history of affected individuals is unlikely. For most ARCA there is no specific drug treatment except for coenzyme Q10 deficiency and abetalipoproteinemia.
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PMID:Autosomal recessive cerebellar ataxias. 1711 70

A defective response to DNA damage is observed in several human autosomal recessive ataxias with oculomotor apraxia, including ataxia-telangiectasia. We report that senataxin, defective in ataxia oculomotor apraxia (AOA) type 2, is a nuclear protein involved in the DNA damage response. AOA2 cells are sensitive to H2O2, camptothecin, and mitomycin C, but not to ionizing radiation, and sensitivity was rescued with full-length SETX cDNA. AOA2 cells exhibited constitutive oxidative DNA damage and enhanced chromosomal instability in response to H2O2. Rejoining of H2O2-induced DNA double-strand breaks (DSBs) was significantly reduced in AOA2 cells compared to controls, and there was no evidence for a defect in DNA single-strand break repair. This defect in DSB repair was corrected by full-length SETX cDNA. These results provide evidence that an additional member of the autosomal recessive AOA is also characterized by a defective response to DNA damage, which may contribute to the neurodegeneration seen in this syndrome.
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PMID:Senataxin, defective in ataxia oculomotor apraxia type 2, is involved in the defense against oxidative DNA damage. 1756 89

Autosomal recessive cerebellar ataxias are a phenotypically and genetically heterogeneous group of diseases. Major forms can be distinguished on the basis of clinical signs, age of onset, biochemical parameters or genotypes. To develop rational diagnostic strategies, phenotypic information, e.g., age of onset combined with population-specific disease frequencies could be highly favourable. We tested this hypothesis for single candidate loci and mutations in North European ataxia patients with juvenile and early adult onset. While we could prove that Friedreich ataxia (FRDA) is frequent in Germany, only few patients with ataxia-oculomotor apraxia type 1 (AOA1) and type 2 (AOA2) were diagnosed. The frequency of the mitochondrial recessive ataxia syndrome (MIRAS) and the infantile onset spinocerebellar ataxia (IOSCA) in this population remains unknown since no case with the common mutation of the corresponding gene was detected.
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PMID:Investigation of recessive ataxia loci in patients with young age of onset. 1805 31

Ataxia with ocular apraxia type 2 (AOA2) is an autosomal recessive, early onset ataxia caused by mutations in the senataxin (SETX) gene. Ocular apraxia and increased levels of alpha-fetoprotein are characteristic but not obligate markers of the disease. AOA2 is allelic with ALS4, a motor neuron disorder of early onset and autosomal dominant inheritance. We observed a two generation family with ataxia which started at age 14 and 17 in two sibs and at age 23 in their paternal uncle.Oculomotor disturbances included strabismus, saccadic pursuit and gaze evoked nystagmus. MRI revealed severe cerebellar atrophy. All patients presented pronounced peripheral neuropathy with wasting of hand and leg muscles resembling distal motor neuronopathy. Increased alphafetoprotein levels triggered genetic analyses of SETX. We found the sib pair to be compound heterozygous for a single base deletion c.2835delC, resulting in a frameshift mutation and causing nonsense related mRNA decay, and a base exchange c.6106G > A, resulting in abnormal splicing and skipping of exon 15. The similarly affected uncle was homozygous for the c.6106G > A mutation probably due to distant consanguinity in the paternal branch of the family. Pseudodominant occurrence in two generations has not been described before in AOA2 and led, in this family, to false categorization as dominant ataxia before SETX mutations were detected. Clinically this family presented with a phenotype combining typical features of AOA2 and ALS4; thus extending the phenotypic spectrum of SETX mutations.
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PMID:"Pseudodominant inheritance" of ataxia with ocular apraxia type 2 (AOA2). 1835 Mar 59


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