title: SCA8 repeat expansions in ataxia: a controversial association.
abstract: The observation of large SCA8 alleles in healthy control subjects and nonataxic patients, together with a lack of segregation of the expanded repeat with ataxia in several families, has raised questions about the pathogenic role of the SCA8 expansion. The authors found allele sizes within the proposed pathogenic range in three patients with ataxia of unknown etiology, in two individuals from pedigrees with either SCA2 or Friedreich's ataxia, and in two patients with Alzheimer's disease. Sizing of SCA8 alleles should not be a routine diagnostic test until its etiologic role is clarified and the pathogenic threshold is determined.
authors.affiliation: Neurogenetics Program, Department of Neurology, UCLA School of Medicine, Los Angeles 90095, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Sobrido
authors.forename: J A
authors.initials: JA
authors.lastname: Cholfin
authors.forename: S
authors.initials: S
authors.lastname: Perlman
authors.forename: S M
authors.initials: SM
authors.lastname: Pulst
authors.forename: D H
authors.initials: DH
authors.lastname: Geschwind
mesh_terms: D000328:Adult; D000544:Alzheimer Disease / Q000235:genetics / Q000473:pathology; D005260:Female; D005621:Friedreich Ataxia / Q000235:genetics / Q000473:pathology; D005787:Gene Frequency; D005817:Genetic Counseling; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics*; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D020754:Spinocerebellar Ataxias / Q000235:genetics* / Q000473:pathology; D019680:Trinucleotide Repeat Expansion
chemical_list: C415906:ATXN8OS gene product, human; D009419:Nerve Tissue Proteins; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated