Congenital heart malformations: aetiology and associations.

The causes of congenital heart malformations are complex and include a major contribution by genetic factors. These can be considered under the headings of chromosomal, single gene and multifactorial. Almost any degree of autosomal imbalance, whether a full trisomy or a tiny microdeletion, can cause a cardiac malformation. Recent research has identified several developmental genes which play an important role in cardiac formation: these are discussed with regard to laterality, septation and vascular morphogenesis. Hypothetical 'polygenes', which may contribute to non-syndromal 'multifactorial' cardiac malformations have yet to be identified. Well-known cardiac malformation syndrome associations are described and simple guidelines are presented to help in the assessment and investigation of an affected neonate who has additional multiple dysmorphic features. Copyright 2001 Harcourt Publishers Ltd.