BATF2 (basic leucine zipper transcription factor, ATF-like 2) is a 274 amino acid protein that localizes to the nucleus and contains one bZIP domain, suggesting that it may be involved in transcriptional regulation. The gene encoding BATF2, which is expressed as multiple alternatively spliced isoforms, is located on human chromosome 11. With approximately 135 million base pairs and 1,400 genes, chromosome 11 comprises approximately 4% of human genomic DNA and is considered a gene and disease association dense chromosome. The chromosome 11 encoded Atm gene is important for regulation of cell cycle arrest and apoptosis following double strand DNA breaks. Atm mutation leads to the disorder known as ataxia-telangiectasia. The blood disorders Sickle cell anemia and thalassemia are caused by HBB gene mutations, while Wilms’ tumors, WAGR syndrome and Denys-Drash syndrome are associated with mutations of the WT1 gene. Jervell and Lange-Nielsen syndrome, Jacobsen syndrome, Niemann-Pick disease, hereditary angioedema and Smith-LemliOpitz syndrome are also associated with defects in chromosome 11-encoded genes.