CNTD2 (cyclin N-terminal domain containing 2) is a 155 amino acid protein that contains one cyclin N-terminal domain and is encoded by a gene that maps to human chromosome 19q13.2. Chromosome 19 consists of approximately 63 million bases and makes up over 2% of human genomic DNA. Chromosome 19 is recognized for having the greatest gene density of the human chromosomes. It is the genetic home for a number of immunoglobulin superfamily members, including killer cell and leukocyte Ig-like receptors, various ICAMs, the CEACAM and PSG families, and Fc?receptors. Key genes for eye color and hair color also map to chromosome 19. Peutz-Jeghers syndrome, spinocerebellar ataxia type 6, the stroke disorder CADASIL, hypercholesterolemia and insulin-dependent diabetes have been linked to chromosome 19. Translocations with chromosome 19 and chromosome 14 can be seen in some lymphoproliferative disorders and typically involve the proto-oncogene Bcl-3.