RNA toxicity is a component of ataxin-3 degeneration in Drosophila.

Polyglutamine (polyQ) diseases are a class of dominantly inherited neurodegenerative disorders caused by the expansion of a CAG repeat encoding glutamine within the coding region of the respective genes. PolyQ has been thought to cause neurodegeneration due to protein toxicity. In contrast, pathogenesis in other repeat diseases, such as myotonic dystrophy, is thought to result from the expression of toxic RNA repeats. Here evidence is provided that pathogenesis caused by ataxin-3, which contains CAG repeats, also involves an RNA-mediated component.