Thanks for your reply, Rich. I thought those studies were very interesting, too. They all described a pathology, but as far as I could see from the abstracts, only one (Pietrangelo) attempted to consider a cause, and it was an alteration in gene expression, which was only a proximal cause. I wondered if the methylation block could produce that alteration in gene expression, and it sounds like you're saying yes, it could. What's frustrating to me is that, regardless of whether we agree on an ultimate cause, we have all these replicated pathologies--just like in a lot of well-accepted diseases--yet it's still considered to have unexplained symptoms and be controversial whether it's a physiological disease or not (even whether it's a physiological disease in a subset of broadly-defined CFS). I also agree that this is a cellular disease, and that cellular disease deserves a new category because it spans everything.