Cloning of the SCA7 Gene Reveals a Highly Unstable CAG Repeat Expansion

Nat Genet. 1997 Sep;17(1):65-70. doi: 10.1038/ng0997-65.

Abstract

The gene for spinocerebellar ataxia 7 (SCA7) has been mapped to chromosome 3p12-13. By positional cloning, we have identified a new gene of unknown function containing a CAG repeat that is expanded in SCA7 patients. On mutated alleles, CAG repeat size is highly variable, ranging from 38 to 130 repeats, whereas on normal alleles it ranges from 7 to 17 repeats. Gonadal instability in SCA7 is greater than that observed in any of the seven known neuro-degenerative diseases caused by translated CAG repeat expansions, and is markedly associated with paternal transmissions. SCA7 is the first such disorder in which the degenerative process also affects the retina.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Age of Onset
  • Aged
  • Alleles
  • Amino Acid Sequence
  • Ataxin-7
  • Chromosome Mapping
  • Chromosomes, Artificial, Yeast
  • Chromosomes, Human, Pair 3*
  • Cloning, Molecular
  • Female
  • Genetic Markers
  • Genetic Variation
  • Genomic Imprinting
  • Humans
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Nerve Tissue Proteins / biosynthesis
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / genetics*
  • Retina / pathology
  • Retinal Degeneration / genetics
  • Retinal Degeneration / physiopathology
  • Spinocerebellar Degenerations / genetics*
  • Spinocerebellar Degenerations / mortality
  • Spinocerebellar Degenerations / physiopathology
  • Trinucleotide Repeats*

Substances

  • ATXN7 protein, human
  • Ataxin-7
  • Genetic Markers
  • Nerve Tissue Proteins

Associated data

  • GENBANK/AJ000517