The phenotype of an individual is the result of complex interactions between genotype, epigenome and current, past and ancestral environment, leading to lifelong remodelling of our epigenomes. Various replication-dependent and -independent epigenetic mechanisms are involved in developmental programming, lifelong stochastic and environmental deteriorations, circadian deteriorations, and transgenerational effects. Several types of sequences can be targets of a host of environmental factors and can be associated with specific epigenetic signatures and patterns of gene expression. Depending on the nature and intensity of the insult, the critical spatiotemporal windows and developmental or lifelong processes involved, these epigenetic alterations can lead to permanent changes in tissue and organ structure and function, or to reversible changes using appropriate epigenetic tools. Given several encouraging trials, prevention and therapy of age- and lifestyle-related diseases by individualised tailoring of optimal epigenetic diets or drugs are conceivable. However, these interventions will require intense efforts to unravel the complexity of these epigenetic, genetic and environment interactions and to evaluate their potential reversibility with minimal side effects.
Clin Chem Lab Med 2007;45:321–7.