TREX2 and psoriasis: The Trex2 gene encodes for an enzyme with exonuclease activity, such enzymes are normally involved in DNA replication and repair, but TREX2 appears to both alter and maintain genome stability, playing a role in DNA-repair.23 This particular exonuclease is best known for a role in skin repair after DNA damage.24 Supporting a role of this gene for injury progression is that Trex2 deficient mice have a milder inflammatory response to induced psoriasis-like phenotype, with down-regulation of genes related to immune cell chemotaxis, cell killing, interferon responses and apoptosis.24