Human morbid genetics revisited: relevance of epigenetics

Identification of genes predisposing their carrier to complex diseases is a much more complicated task than finding genes involved in simple mendelian diseases. The slow progress in the genetic research of complex diseases co uld be due to limitations in the basic research strategy, which is almost e xclusively orientated to the detection of disease-related DNA mutations or polymorphisms. I argue in this article that epigenetic misregulation of gen es is more consistent with the features of complex diseases than is DNA seq uence variation, and therefore that epigenetic factors could be important i n understanding the origins of complex diseases.