Rare acelerated aging syndromes have a great deal to teach us about the biochemistry of aging and cancer. Great progress has been made in deciphering progeria, and now Werner's syndrome research is catching up : "One reason we are particularly interested in WRN is because Werner's syndrome is unusual among premature-aging diseases, in that children are born normal and show no signs of disease until early adulthood. This gives us a better chance of clearly separating defects in development from aging. ... Among other things, WRN is involved in repairing double-strand breaks, single-strand breaks, replication forks and junctions, even DNA-RNA duplexes. How does one protein know how to interact in so many different processes? If we can understand how this unique protein works, we'll have a key to how all these pathways work in human beings." Understanding DNA repair is the first step towards greatly improving DNA repair.