In Xenopus, Gremlin 1 belongs to a novel gene family that act as BMP antagonists in embryonic explants. The human homolog of Gremlin 1(CKTFS1B1) is localized on human chromosome 15q13--> q15. Gremlin 1-specific mRNA is expressed in different human tissues, including brain, ovary, intestine and colon. It has been suggested that down-regulation of Gremlin 1 is associated with tumor progression, and support the hypothesis that human Gremlin 1 may play an important role during both neuroembr