The recurrence risk in congenital heart disease

We have studied 1148 'isolated" cases of congenital heart disease, taken from a general series of 1255 cases. The recurrence risk ranged from 0.9% for relatives of male cases of VSD and for female cases of aortic stenosis to 10.5% for relatives of female cases of atrioventricularis communis; mean value 2.5%. Heritability ranged from 50% to 95%, mean 65%. Full concordance was more frequent in 1st-degree relatives of Fallot's tetralogy patients, while discordance was common in more distant relatives. We propose a hypothesis of several overlapping polygenic systems for the causation of CHD.