NODAL coreceptor involved in the correct establishment of the left-right axis. May play a role in mesoderm and/or neural patterning during gastrulation. Does not exhibit a typical GPI-signal sequence. The C-ter hydrophilic extension of the GPI-signal sequence reduces the efficiency of processing and could lead to the production of an secreted unprocessed form. This extension is found only in primates. N-glycosylated. The disease is caused by variants affecting the gene represented in this entry. Belongs to the EGF-CFC (Cripto-1/FRL1/Cryptic) family. This gene differs from CFC1B by only one residue at position 78:R -> W. R78W is also thought to be a CFC1 polymorphism which has been shown to lead to a different cell surface distribution and activity (PubMed:11799476 and PubMed:11062482).