Progress study on the mechanism of CAG repeats dynamic mutation in polyQ disease

Polyglutamine (polyQ) disease is a group of neurodegenerative disorders caused by abnormal expansion of CAG repeats within coding regions of certain causative genes, which are translated into a series of abnormally expanded polyQ tracts causing cytotoxicity. So far, nine diseases caused by expanded polyQ tracts have been demonstrated including Huntington's disease (HD), spinobulbar muscular atrophy (SBMA), dentatorubral⁃pallidoluysian atrophy (DRPLA) and several spinocerebellar ataxias subtypes (SCA). In human, long CAG repeats tend to expand during transmissions from parent to offspring, named as dynamic mutation, leading to an earlier age of disease onset and more severe symptoms in subsequent generations. The review presents some novel mechanisms based on dynamic mutation. DOI：10.3969/j.issn.1672⁃6731.2012.03.02