DRD2 and Huntington disease: Cluster centroids Drd2-5 (up-regulation), Drd1-6 (up-regulation), Drd1-8 (down-regulation), Interneurons-0 (down-regulation), Interneurons-4, and Astrocytes-4 (up-regulation) implicate ‘DNA repair’ or ‘DNA damage response’, suggesting that DNA repair is a biological process that is significantly altered in HD models in all four cell types.