Schematic representation of the ERGIC-53 gene showing mutations causing combined F5F8D (above the gene) and normal polymorphisms (below). Exons, indicated by rectangles, are numbered from 1 to 13 and are drawn to scale. The coding portion of the gene is shaded, with the white portion of exon 1 representing the 5′ UTR and the white portion of exon 13 the 3′ UTR, the exact size of which is unknown. The introns are indicated by narrow lines and are not to scale.