(A) The mechanism of a secondary epimutation. A DNA alteration at an imprinting center (IC) indirectly influences and alters the methylation pattern (black and white triangles) at another locus, which could be in cis or in trans. (B) In primary epimutation, the external stimulus (whether environmental or stochastic) directly alters the methylation.
Czyz et al. BMC Medicine 2012 10:93 doi:10.1186/1741-7015-10-93