Using a case-control study design with a gel-based approach (two-dimensional gel electrophoresis and liquid chromatography tandem mass spectrometry) two proteins (complement factor H [CFH] and alpha-2-macroglobulin [A2M]) were observed as potential markers of AD [1], both of which were subsequently replicated by independent groups [2], [3]. The gene discussed is CFH; the disease is Alzheimer disease.