C5orf20 is a intronless gene is specifically expressed in dendritic cells (DCs), which are potent antigen-presenting cells involved in activating naive T cells to initiate antigen-specific immune response. The encoded protein is localized mainly in the perinucleus. One of the alleles (A T) of this gene, that causes premature translation termination at aa 117, has been associated with an increased prevalence of major depression in humans