Histone deacetylase 2 is an enzyme that in humans is encoded by the HDAC2 gene. This gene product belongs to the histone deacetylase family. Histone deacetylases act via the formation of large multiprotein complexes and are responsible for the deacetylation of lysine residues on the N-terminal region of the core histones (H2A, H2B, H3 and H4). This protein also forms transcriptional repressor complexes by associating with many different proteins, including YY1, a mammalian zinc-finger transcription factor. Thus it plays an important role in transcriptional regulation, cell cycle progression and developmental events. Betz et al. (1998) performed PCR using HDAC2-specific primers to screen a somatic cell hybrid mapping panel. They mapped the HDAC2 gene to human chromosome 6q21, a region of the genome altered in some cancers, including retinoblastoma.