The highest ranking PKP2-related gene in Fam2 is the interferon regulatory factor 1 (IRF1), which harbors a rare, deleterious-predicted missense variant in the affected male patient Fam2.II.1 and his healthy father Fam2.I.1. IRF1 inhibits cell growth in coronary artery smooth muscle cells . Repression of IRF1 has lead to a higher susceptibility to the formation of neointima (scar tissue) following vessel injury in mice .