Figure 2: Panel A shows the methodology for the 2D DiGE technique. Individual samples are labelled with fluorescent Cy dyes that can be combined and resolved on a single 2D gel. The gel is then scanned for the three dyes creating overlaid images which give us a look at the serum proteome highlighting changes in subtle charge and mass in glycoproteins from patients with CDG that have an inconclusive transferrin results. Panel B shows overlaid 2D DiGE images of glycoforms of a-1-antitrypsin and caeruloplasmin showing typical charge and mass change profiles seen in CDG-I and CDG-II. In CDG-I, the abnormally glycosylated proteins have unusual mass and charge and, compared to the normal proteins, are “shifted” to the right and down; in CDG-II, the abnormally glycosylated proteins are “shifted” to the right.