Lefty1 - left right determination factor 1

This gene encodes a secreted ligand of the TGF-beta (transforming growth factor-beta) superfamily of proteins. Ligands of this family bind various TGF-beta receptors leading to recruitment and activation of SMAD family transcription factors that regulate gene expression. The encoded preproprotein is proteolytically processed to generate the mature protein, which plays a role in left-right asymmetry determination of organ systems during development. Mice lacking a functional copy of this gene exhibit embryonic lethality and defects in left-right patterning. [provided by RefSeq, Aug 2016]