Aspects of the aetiology of congenital heart disease

A concise overview of current knowledge on the aetiology ofcongenital heart disease is provided. At present, only 10 to20% of the cases occurring in neonates can be attributed toknown risk factors. Recurrence within relatives, chromosomalanomalies, genetic disorders, maternal diseases and teratogenexposure are addressed briefly; contemporary research modelsand methods, e.g. embryology and genetics and molecular biology,are referred to. A major innovation has been the introductionof the concept of common pathogenetic pathways. Thus, differentteratogenic factors or risk-factors may affect normal developmentat an identical stage and cause similar malformations. Also,the importance of timing of an event is stressed. If the timeframe of exposure does not coincide with embryogenesis any teratogeniceffect may be missed. Large-scale epidemiological studies on fetuses and neonateswith congenital heart disease are introduced as a third modeof research on the aetiology, although this approach is notused efficiently at present; cases of intra-uterine death canbe considered a valuable source of information that needs furtherattention. Combined, the above three lines of research may proveproductive, but the design of a comprehensive research projectwould need to be handled carefully. Possibilities for preventionof the occurrence of cardiovascular malformations are reported.Through lack of knowledge of causality, at present, only secondaryprevention may be possible and hence deserves attention. However,there appears to be no provision for thorough pre-natal screeningtests for congenital heart disease in an unselected population.