PLPP3 and coronary artery disorder: These genes include PPAP2B, which encodes a member of the phosphatidic acid phosphatase (PAP) family and has been implicated in coronary artery disease risk (Schunkert et al. 2011; Dichgans et al. 2014); STEAP3, which encodes an endosomal ferrireductase required for efficient transferrin-dependent iron uptake; and AKNA, which encodes a transcription factor that specifically activates the expression of the CD40 receptor and its ligand CD40L/CD154 on lymphocyte cell surfaces, which are critical for antigen-dependent-B-cell development (Figure 4A).