Trinucleotide Repeat Disorder

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A class of clinically heterogenous disorders, defined by the presence of an abnormal and unstable expansion of DNA—triplet repeats—in the mutant gene, with up to 200 copies of the repeated trinucleotide
Examples Hereditary—CAG repeats (Huntington’s disease, Kennedy’s disease), CGG (fragile X syndrome), GCT (myotonic dystrophy, spinal and bulbar muscle atrophy); Acquired—some forms of colourectal CA
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References in periodicals archive ?
It is a trinucleotide repeat disorder like Huntington's disease and is caused by excessive numbers of CGG repeats in the promoter region for the FMR1 gene on the X chromosome, which causes the X chromosome to appear broken in this region in certain cell cultures.
FA is now known to be an autosomal recessive trinucleotide repeat disorder, with the most common mutation being an expanded GAA triplet repeat in intron 1 on both alleles of FXN.
Pathogenic examples related to trinucleotide repeats have their own collective name as trinucleotide repeat disorders. One of the best-known examples of these is Huntington's disease.
Trinucleotide repeat disorders. Ann Rev Neurosci 2007; 30: 575-621, doi: 10.1146/annurev.neuro.
The next major class is the trinucleotide repeat disorders. The classical example here is Fragile X, whereby a repeating CGG motif expansion (growing to over thousands of nucleotides in some cases) causes disease.
They cover the basic mechanisms of neurodegeneration, Alzheimer's disease and aging, tauopathies, synucleinopathies, trinucleotide repeat disorders, prion disorders, frontotemporal lobal degeneration and amyotrophic lateral sclerosis/motor neuron disease, and other neurodegenerative disorders.
We now understand that it is one of a group of conditions called trinucleotide repeat disorders, and a very brief description of the chemical structure of chromosomes will help to explain how these disorders arise.
Molecular genetic analysis of trinucleotide repeat disorders (TRDs) in Indian population and application of repeat primed PCR.
Testing for FXS and similar trinucleotide repeat disorders (e.g., myotonic dystrophy, Huntington disease, spinocerebellar ataxias, spinal and bulbar muscular atrophy, and Friedreich ataxia) is typically performed using Southern blot (5) or, more recently, by PCR and capillary electrophoresis (6, 7).
Trinucleotide repeat disorders. Annu Rev Neurosci 2007;30:575-621.