The current body of research examining the function of mast cells in CRS suggests that they may contribute to the pathophysiology of eosinophilic CRS, as evidenced by the significant increase in membrane-attached IgE-positive mast cells in patients with eosinophilic CRS compared to those with non-eosinophilic CRS [28]. The gene discussed is IGHE; the disease is congenital rubella syndrome.