However, since Dp3Tyb mice that do not have an increased dosage of these genes show CHD (8), and Dp1TybDyrk1a+/+/- mice that still have three copies of the genes do not show CHD (this study), our results imply that increased dosage of the interferon receptor genes is neither necessary nor sufficient to cause CHD. The gene discussed is IFNAR2; the disease is coronary artery disorder.