This gene encodes a WD repeat protein, which interacts with Cockayne syndrome type B (CSB) protein and with p44 protein, a subunit of the RNA polymerase II transcription factor IIH. Mutations in this gene have been identified in patients with hereditary disease Cockayne syndrome (CS). CS cells are abnormally sensitive to ultraviolet radiation and are defective in the repair of transcriptionally active genes. [provided by RefSeq, Jul 2008]