The study of epigenetic changes during embryonic stem (ES) or neural stem cell (NSC) differentiation is ideal for elucidating the mechanisms specific to these epigenetic regulatory processes. Recent studies have been focusing on the regulation of ES cell pluripotency, differentiation, and potential regulation of OCT4, Nanog and Sox2 by epigenetic mechanisms (16-18,25); however, the epigenetic modification during NSC differentiation is largely unknown. Nevertheless, erroneous epigenetic alterations are known to interrupt developmental events, particularly in the nervous system, leading to conditions such as Rett's syndrome (3), immunodeficiency centromeric instability and facial syndrome (ICF) (9,14), and Prader-Willi/Angelman syndrome (15,24).
