Report about examinations in the families of 24 children with severe, lethal malformations of the heart. At all probands, who had died before 6th month of life, the, cause of death could be insured by autopsy.
Under 16 children with lethal defects of the septum 6 suffered from mongolism (additional one with enterocystom of oesophagus, one with double inguinal rupture, one with cleft palate and one with microcephaly and atresia of the duodenum). In none of these families any sign for heredital cause or « ovarial insufficience » of the mother could be found.
In the families of 10 children with defect of the septum without additional malformation two times the clinical examinations of the mother showed distinct symptoms of heart decompensation without evidence for acquired heart diseases. In two other families beside the probands other family-members with inborn heart diseases could be found, one time an autoptical proved defect of the septum at a cousin of our probands father.
During these families seem to show heredity of lethal defects of the septum in an irregular dominant inheritance, only one time in an «isolated » case of lethal defects of the septum the cause of the malformation may be seen in severe bleedings of the mother during pregnancy.
In an earlier report about similiar examinations two siblings could be found, one of them had only a defect of the septum, the other had beside a defect of septum, a severe harelip and cleft palate, a hernia diaphragmatica, a hypoplasia of the fingers and a microcephalia combined with arhinencephalia. The father of another child with a defect of the septum suffered from coloboma of the iris.
It is supposed, that there are several gens to septum defects, that means Heterogenie. Polyphenical effects of the gens result differential forms of manifestation, not only at the heart. There were no differences found on homozygotics and heterozygotics.
Among 8 children with differential other malformations of the heart (5 cases of severe stenosis of the aorta, 1 case of malformation of the pulmonal valve, 1 case of trasposition of the big arterias) only one time could be found the same anomaly (open foramen ovale, open ductus arteriosus) on two cousins (each of them have an non dissecated brother with equal clinical symptoms). Because the parents were non blood-related also in this family an unregular dominant inheritance of the anomalies at the foramen ovale and the ductus arteriosus seems probable.
Systematical examination in families with lethal malformations are further equal necessary as explications of pregnancy harms for exclusion of exogen factors.