Accumulation of different congenital heart defects in one pedigree

In one kindred nine cases of congenital heart defect of several different types were diagnosed. Confirmation of the diagnoses was achieved at surgery in five cases and at post‐mortem examination in two. One pair of affected sibs born to healthy parents was found in each of three generations. Transmission from parent to child occurred once. The defects might possibly be due to a major gene exerting its effect in the heterozygote condition. This would imply a highly reduced penetrance and extraordinarily wide variation in expressivity.