Ring finger protein 168 is a protein that in humans is encoded by the RNF168 gene. It is mapped to 3q29. This gene encodes an E3 ubiquitin ligase protein that contains a RING finger,a motif present in a variety of functionally distinct proteins and known to be involved in protein-DNA and protein-protein interactions. The protein is involved in DNA double-strand break (DSB) repair. Mutations in this gene result in Riddle syndrome.