This Month in Genetics

Huntington disease is a common example used for initiating discussion about presymptomatic genetic testing when no therapeutic intervention is available. Recent work in mice provides a glimmer of hope that this might not always be true. Budworth et al. knew that the enzyme OGG1 is involved in DNA repair and, as a by-product, contributes to Htt-repeat instability. Because loss of OGG1 activity prevents somatic expansion of Htt repeats, Budworth et al. used this as a tool to explore in mice the role of somatic expansion in the age of onset of Huntington disease.