GPC3 and infection: GPC3 encodes a cell surface proteoglycan that is linked to the outer leaflet of the plasma membrane by a glycosyl phosphatidyl inositol.[18,19] Proteoglycans in the extracellular matrix can interact with receptors on the surface of immune cells to form a defensive barrier against the harmful macromolecules.[20,21] It seems plausible that the patient's susceptibility to infection would have been increased by his SGBS1, although we cannot be certain.