A 13-fold increase in the incidence of DORV with AVSD—40% with Tie2+/Cre/Nkx2-5+/Cre: Lrp1f/f double Cre deletion vs. 3% with Tie2+/Cre: Lrp1f/f—was observed. This evidence concerns the gene TEK and familial atrioventricular septal defect.