Genome-wide association studies confirmed the existence of several variants belonging to different genes associated with IS and their specific subtypes, such as paired-like homeodomain transcription factor 2 (PITX2) and Zinc Finger Homeobox 3 (ZFHX3) in the cardioembolic stroke [21], histone deacetylase 9 (HDAC9), and cyclin dependent kinase inhibitor (CDKN) in the large-vessel stroke subtype [22]. The gene discussed is HDAC9; the disease is cardioembolic stroke.