© 2016 Elsevier Ltd. Four exons of the CgFrep1 gene (3333 bp long) encode a putative fibrinogen-related protein (324 aa) bearing a single C-terminal FBG domain. Transcripts of the gene obtained from hemocytes of different Pacific oysters show prominent individual variation based on SNP and indels of tandem repeats resulted in polymorphism of N-terminus of the putative CgFrep1 polypeptide. The polypeptide chain bears N-terminal coiled-coil region potentially acting as inter-subunit interface in the protein oligomerization. It is suggested that CgFrep1 gene encodes the oligomeric lectin composed of at least two subunits.