The article in this issue of the Journal by Brothers et al. ( 1) is the first study to show convincingly that the anomalous aortic origin of a coronary artery, that is, the left main coronary artery arising from the right sinus of Valsalva ( ALCA) or the right coronary artery arising from the left sinus of Valsalva ( ARCA), is familial. It is no surprise that coronary anomalies are familial. Given the fact that the embryology of coronary artery development, in both the course they take on the epicardium and their origin from the aorta, is according to genetic plan, a mutation in the genetic coding can result in these anomalies of coronary origin. If the mutation is in the somatic cells after germ cell differentiation, then the anomaly is confined to that individual, but if it involves the germ cells, then it can be passed on to future generations and becomes a familial anomaly.