trinucleotide repeat expansion


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trinucleotide repeat expansion

[‚trī¦nü·klē·ə‚tīd ri′pēt ik‚span·shən]
(genetics)
An increase in the number of copies of a trinucleotide that is normally already present in multiple adjacent copies. For example, the X-linked mental retardation 1 (XLMRI) locus in humans usually contains 6-50 tandem repeats of CCG, but this is expanded to 200-2000 copies in the fragile-X syndrome.
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References in periodicals archive ?
Frequency of SCA1, SCA2, SCA3/MJD, SCA6, SCA7, and DRPLA CAG trinucleotide repeat expansion in patients with hereditary spinocerebellar ataxia from Chinese kindreds.
Trinucleotide repeat expansion in the FRAXE locus is not common among institutionalized individuals with non-specific developmental disabilities.
Relationship between trinucleotide repeat expansion and phenotypic variation in Huntington's disease.
A novel PCR-based approach for the detection of the Huntington disease associated trinucleotide repeat expansion.
The abbreviated process likely will be sufficient for all mutations except trinucleotide repeat expansion mutations, which would require special handling as discussed above.
After a 10-year struggle, during which fundamental strategies of positional cloning were developed, the causative mutation, a CAG trinucleotide repeat expansion, was identified (4).