Hereditary Factors in Atrial Septal Defect

Abstract

One hundred families ascertained through a proband's having atrial septal defect (ostium secundum) were studied. Selection of certain pedigrees from the overall data could lead to the conclusion that atrial septal defect is inherited as a Mendelian dominant or a Mendelian recessive, depending on the pedigrees selected. Analysis of the overall data from this study and from the literature suggests multifactorial inheritance of atrial septal defect as the explanation most consistent with available observations. The distinction between inheritance of a defect through single factor or multifactorial modes is of more than academic interest. From the point of view of genetic counseling, the risk to the newborn is not fixed in multifactorial inheritance but increases with the number of affected relatives. From the point of view of prevention, environmental hazards such as drugs and illnesses may play an important role in the production of defects showing multifactorial inheritance.