SPINK4 is an 86 amino acid secreted protein containing one kazal-like domain, which has been suggested to play a role in central nervous system disorders associated with dopamine dysregulation. Expressed in the gastrointestinal tract, central nervous system, bone marrow and peripheral blood, SPINK4 is moderately expressed in spleen and is encoded by a gene mapping to human chromosome 9p13.3. Human chromosome 9 houses over 900 genes and comprises nearly 4% of the human genome. Hereditary hemorrhagic telangiectasia, which is characterized by harmful vascular defects, and Familial dysautonomia, are both associated with chromosome 9.