For example, cluster 3 in the DEGs contained NK2 homeobox 5 (Nkx-2.5), which is essential for maintenance of ventricular identity [41]; paired like homeodomain 2 (PITX2) and paired related homeobox 1 (PRRX1), which are both associated with the atrial fibrillation and cardioembolic ischemic stroke variants loci [42–44]; and Meis homeobox 1 (MEIS1), which is required for heart development in mice [45]. The gene discussed is PRRX1; the disease is atrial fibrillation.