gG receptor FcRn large subunit p51 is a protein that in humans is encoded by the FCGRT gene. This gene encodes a receptor that binds the Fc region of monomeric immunoglobulin G. The encoded protein transfers immunoglobulin G antibodies from mother to fetus across the placenta. This protein also binds immunoglobulin G to protect the antibody from degradation. In addition, it is postulated that long-range cis inactivation of the FCGRT gene is responsible for hypercatabolism of IgG in myotonic dystrophy. The FCGRT gene is closely situated to the DMPK gene, which is mutant in DM.