title: Hereditary ataxias.
abstract: There are many causes of hereditary ataxia. These can be grouped into categories of autosomal recessive, autosomal dominant, and X-linked. Molecularly, many of them are due to trinucleotide repeat expansions. In Friedreich ataxia, the trinucleotide repeat expansions lead to a "loss of function." In the dominant ataxias, the expanded repeats lead to a "gain of function," most likely through accumulation of intranuclear (and less commonly cytoplasmic) polyglutamine inclusions. Channelopathies can also lead to ataxia, especially episodic ataxia. Although phenotypic characteristics are an aid to the clinician, a definitive diagnosis is usually made only through genotypic or molecular studies. Genetic counseling is necessary for the testing of symptomatic and asymptomatic individuals. No effective treatment is yet available for most ataxic syndromes, except for ataxia with isolated vitamin E deficiency and the episodic ataxias.
authors.affiliation: Department of Neurology, Mayo Clinic Scottsdale, Ariz., USA.
authors.forename: V G
authors.initials: VG
authors.lastname: Evidente
authors.forename: K A
authors.initials: KA
authors.lastname: Gwinn-Hardy
authors.forename: J N
authors.initials: JN
authors.lastname: Caviness
authors.forename: S
authors.initials: S
authors.lastname: Gilman
mesh_terms: D000067696:Ataxin-1; D000067699:Ataxin-3; D000067719:Ataxin-7; D000067528:Ataxins; D005621:Friedreich Ataxia / Q000235:genetics; D008040:Genetic Linkage; D006801:Humans; D017827:Machado-Joseph Disease / Q000235:genetics; D009154:Mutation; D020191:Myoclonic Epilepsies, Progressive / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D010641:Phenotype; D011506:Proteins / Q000235:genetics; D012097:Repressor Proteins; D020754:Spinocerebellar Ataxias / Q000150:complications / Q000235:genetics*; D013577:Syndrome; D014960:X Chromosome
chemical_list: C000593749:ATXN1 protein, human; C000593829:ATXN7 protein, human; D000067696:Ataxin-1; D000067719:Ataxin-7; D000067528:Ataxins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011506:Proteins; D012097:Repressor Proteins; C092341:ATXN3 protein, human; D000067699:Ataxin-3