Early-life origin of adult disease: evidence from natural experiments.

Until the present time, disease susceptibility was believed to be determined solely by the genetic information carried in the DNA sequence. In recent years, however, it has become clear that epigenetic rearrangements play an equally essential role in the disease development and that this process, particularly at key developmental stages, is very susceptible to environmental modulations. The extensive studies, both human and animal, have shown that early-life environment is probably the most important causal component in the etiology of some diseases including cancer as well as metabolic and cardiovascular disorders. This review considers the natural experiment-based evidence regarding the developmental origin of human adult disease.