Follow-up paired comparisons suggest that the tracts dominating the PCA analysis, AF, CB, EmC/IFOF and ILF, fail to do so differentially (AF vs CB: t39 = 1.02, p = 0.316, AF vs ILF: t39 = −0.194, p = 0.848, AF vs EmC/IFOF: t39 = 1.58, p = 0.122, CB vs ILF: t39 = −0.72, p = 0.478, CB vs EmC/IFOF: t39 = 0.31, p = 0.757). This evidence concerns the gene FOXK2 and atrial fibrillation.