Suprabasin is a 247 amino acid secreted protein that is upregulated in differentiating keratinocytes and is though to play a role in epidermal differentiation. Expressed in uterus, skin, thymus and esophagus, suprabasin is encoded by a gene that maps to human chromosome 19q13.12. Chromosome 19 consists of about 63 million bases with over 1,400 genes, making up over 2% of human genomic DNA. Chromosome 19 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 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.