Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2

Nat Genet. 1996 Nov;14(3):269-76. doi: 10.1038/ng1196-269.


The gene for spinocerebellar ataxia type 2 (SCA2) has been mapped to 12q24.1. A 1.1-megabase contig in the candidate region was assembled in P1 artificial chromosome and bacterial artificial chromosome clones. Using this contig, we identified a CAG trinucleotide repeat with CAA interruptions that was expanded in patients with SCA2. In contrast to other unstable trinucleotide repeats, this CAG repeat was not highly polymorphic in normal individuals. In SCA2 patients, the repeat was perfect and expanded to 36-52 repeats. The most common disease allele contained (CAG)37, one of the shortest expansions seen in a CAG expansion syndrome. The repeat occurs in the 5'-coding region of SCA2 which is a member of a novel gene family.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Ataxins
  • Base Sequence
  • Chromosome Mapping
  • Chromosomes, Human, Pair 12*
  • DNA, Complementary / isolation & purification
  • Gene Expression Regulation
  • Humans
  • Molecular Sequence Data
  • Nerve Tissue Proteins
  • Proteins / genetics*
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Spinocerebellar Degenerations / genetics*
  • Trinucleotide Repeats*


  • Ataxins
  • DNA, Complementary
  • Nerve Tissue Proteins
  • Proteins

Associated data

  • GENBANK/U70323
  • GENBANK/U70670
  • GENBANK/U70671