Realm of revertant mosaicism expanding.

In this issue, Lai-Cheong et al. report a patient with Kindler syndrome who showed revertant mosaicism: a patch of normal-looking skin attributable to a reverse mutation. The molecular basis of the reverted patch appeared to be the deletion of a duplicated cytosine, thus restoring the reading frame of FERMT1 transcripts. This finding further pushes the frontier of revertant mosaicism, a phenomenon of spontaneous gene repair, which can be seen with the naked eye in skin.