This gene encodes a member of the lipocalin family of small secretory proteins. Lipocalins are extracellular transport proteins that bind to a variety of hydrophobic ligands. The encoded protein is the primary lipid binding protein in tears and is overproduced in response to multiple stimuli including infection and stress. The encoded protein may be a marker for chromosome aneuploidy as well as an autoantigen in Sjogren's syndrome. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene, and two pseudogenes of this gene are also located on the long arm of chromosome 9. [provided by RefSeq, Nov 2011].