Twisted gastrulation protein homolog 1 is a protein that in humans is encoded by the TWSG1 gene. [5] [6] The protein is a binding protein for bone morphogenetic proteins, similar to Chordin. [7] The Twisted gastrulation gene is expressed in the extraembryonic tissues during organogenesis, and in certain adult tissues such as the lymph nodes, kidneys, liver, and lungs. [8]