Three non-synonymous variations, namely c.286A > G (p.Thr96Ala), c.293A > C (p.Asp98Ala), and c.299T > C (p.Leu100Ser), were reported to affect the second helix of HEY2 in the diseased cardiac tissues of 2 cases with atrioventricular septal defect, suggesting its possible function in the regulation of ventricular septation in humans. The gene discussed is HEY2; the disease is Atrioventricular canal defect.