DNA methylation and gene expression

In the field of studies of the mechanisms of gene expression, much recent work using the methods of genetic engineering, have suggested the hypothesis of a role of DNA methylation (on some cytosines) in the control of gene activity. Undermethylation is generally accompanied by gene expression. A review of studies on DNA methylation in some physiopathologic conditions (such as development and cancer) and of recent therapeutic trials in beta thalassemia, allows to conclude that there is a correlation between DNA methylation pattern and gene expression, rather than a direct causal effect.