Gene-environment interactions: implications for sudden unexpected deaths in infancy.

From the perspective of systems biology, genes and proteins interact to produce complex networks, which in turn interact with the environment to influence every aspect of our biological lives. Recent advances in molecular genetics and the identification of gene polymorphisms in victims of sudden infant death syndrome (SIDS) are helping us better to understand that SIDS, like all other human conditions in health and disease, represents the confluence of specific environmental risk factors interacting in complex ways with specific polymorphisms to yield phenotypes susceptible to sudden and unexpected death in infancy. Failure to consider both genetic and environmental risk factors will impede research progress.