Background：

Consisting of around 63 million bases with over 1，400 genes， chromosome 19 makes up over 2% of human genomic DNA. Chromosome 19 includes a diversity of interesting genes and 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 the killer cell and leukocyte Ig-like receptors， a number of ICAMs， the CEACAM and PSG family， 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 BCL3. The C19orf62 gene product has been provisionally designated C19orf62 pending further characterization.