DNA methylation has been newly discovered as a key controller in gene transcription too. Aberrant DNA methylation changes can cause a number of human diseases such as developmental diseases (ICF syndrome, Prader-Willi and Angelman syndromes etc), ag- ing related diseases (i.e. Alzheimer’s disease), heart disease, diabetes, and autoimmune diseases. Moreover, large amount of evidence implicated that DNA methylation is a key player in cancer development. Dr.