Risk to offspring of parents with congenital heart defects.

The occurrence risk of atrial-septal defect (ASD) and ventricular-septal defect (VSD) was determined in children of 308 adults with these heart lesions, most of which had been surgically corrected. Parents with ASD had 2.6% of their children affected with ASD which is 37 times greater than the estimated population frequency. For VSD, 3.7% of the children of parents with this heart defect were similarly affected. This is 21 times the estimated population frequency. These findings are offered as empirical risk figures for the purposes of genetic counseling. The data were found to approximate closely the predictions of multifactorial inheritance hypothesis for the etiology of congenital heart diseases. In comparing the congenital heart patients with the general population, differences in marriage patterns were detected which could influence fertility and partially offset the increased recurrence risk.