Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0016719 (Friedreich's ataxia)
 2,098 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

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

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

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

Senataxin (SETX) is a DNA-RNA helicase whose C-terminal region shows homology to the helicase domain of the yeast protein Sen1p. Genetic discoveries have established the importance of SETX for neural function, as recessive mutations in the SETX gene cause Ataxia with Oculomotor Apraxia type 2 (AOA2) (OMIM: 606002), which is the third most common form of recessive ataxia, after Friedreich's ataxia and Ataxia-Telangiectasia. In addition, rare, dominant SETX mutations cause a juvenile-onset form of Amyotrophic Lateral Sclerosis (ALS), known as ALS4. SETX performs a number of RNA regulatory functions, including maintaining RNA transcriptome homeostasis. Over the last decade, altered RNA regulation and aberrant RNA-binding protein function have emerged as a central theme in motor neuron disease pathogenesis, with evidence suggesting that sporadic ALS disease pathology may overlap with the molecular pathology uncovered in familial ALS. Like other RNA processing proteins linked to ALS, the basis for SETX gain-of-function motor neuron toxicity remains ill-defined. Studies of yeast Sen1p and mammalian SETX protein have revealed a range of important RNA regulatory functions, including resolution of R-loops to permit transcription termination, and RNA splicing. Growing evidence suggests that SETX may represent an important genetic modifier locus for sporadic ALS. In cycling cells, SETX is found at nuclear foci during the S/G2 cell-cycle transition phase, and may function at sites of collision between components of the replisome and transcription machinery. While we do not yet know which SETX activities are most critical to neurodegeneration, our evolving understanding of SETX function will undoubtedly be crucial for not only understanding the role of SETX in ALS and ataxia disease pathogenesis, but also for delineating the mechanistic biology of fundamentally important molecular processes in the cell.
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PMID:Senataxin, A Novel Helicase at the Interface of RNA Transcriptome Regulation and Neurobiology: From Normal Function to Pathological Roles in Motor Neuron Disease and Cerebellar Degeneration. 2991 23