I was diagnosed with CFS at age ten, after several years of deteriorating health and energy. I've had a couple of "remission" periods, but they never last, and I try to "make hay while the sun shines" during those rare times.
I believe my CFS stems from a bout of Glandular Fever (Mononucleosis) at age six. But I also believe that there is a genetic link, as my mother had something very like CFS in the few years prior to having me. Also, my maternal Grandmother suffered a severe illness in the 1950's which is now believed to be an "outbreak" of CFS.