Members of the immunoglobulin (Ig) superfamily, which includes IGSF1, have a variety of functions, but all appear to play a role in cell recognition and the regulation of cell behavior.Members of the immunoglobulin (Ig) superfamily (see MIM 147100), which includes IGSF1, have a variety of functions, but all appear to play a role in cell recognition and the regulation of cell behavior.[supplied by OMIM].