A possible increase in the incidence of congenital heart defects among the offspring of affected parents.

The incidence of congenital heart disease in the children of 219 probands was determined. Each of these probands had one of four selected defects: atrial septal defect, coarctation of the aorta, aortic valve stenosis or complex dextrocardia. Of their children, 8.8% had substantial congenital cardiac defects. This is a much higher incidence than that reported in most comparable studies. The difference is highly significant statistically and therefore is likely to be genuine. The cause of the high recurrence is probably environmental.