The discovery in 1991 that human diseases can be caused by large-scale expansion of highly unstable trinucleotide repeats has elucidated a new mutation mechanism: heritable unstable DNA. There are 10 possible trinucleotide repeats at the DNA level, but only three have been identified to be involved in human diseases. On the basis of three disease genes, this work provides an overview of the different types of repeat instability in genes and describes how this knowledge can be used diagnostically. The diseases share the ...
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The discovery in 1991 that human diseases can be caused by large-scale expansion of highly unstable trinucleotide repeats has elucidated a new mutation mechanism: heritable unstable DNA. There are 10 possible trinucleotide repeats at the DNA level, but only three have been identified to be involved in human diseases. On the basis of three disease genes, this work provides an overview of the different types of repeat instability in genes and describes how this knowledge can be used diagnostically. The diseases share the unusual characteristic of inheritance with increased severity in successive generations, a phenomenon called anticipation. The anticipation can now be explained by the correlation of increasing repeat length with increased disease severity,
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