Hereditary atrial septal defect. Update of a large kindred
H. T. Lynch, K. Bachenberg, R. E. Harris and W. Becker
A large pedigree wherein members are predisposed to atrial septal defect
(ASD) and associated cardiovascular anomalies has been studied. There were
ten direct line relatives with ASD verified by cardiac catheterization
and/or surgery and in one case by reliable medical history. The pedigree
shows vertical transmission of ASD through four generations. Estimates of
the genetic segregation ratio were near 50%, indicating that predisposition
to ASD among family members was due to a deleterious autosomal dominant
gene. Family members have also manifested other congenital heart anomalies,
consistent with pleiotropic effects of the putative gene.
Electrocardiograms in six ASD patients revealed an absence of prolonged P-R
interval. In the light of prior studies showing prolonged P-R interval in
familial ASD, we suggest the existence of at least two distinct hereditary
varieties of ASD, one with and one without a prolonged P-R interval.
