There is clear evidence of a family tendency toward celiac disease. 5-10% of the first-level relatives (parents, children, and siblings) of diagnosed celiacs may develop celiac disease. The disease affects both sexes, and it can begin at any age, from infancy (as soon as cereal grains are introduced) to later life (even though the individual has consumed cereal grains all along). The onset of the disease seems to require two components: genetic predisposition (two specific genetic markers, called HLA sub-factors, are present in well over 90% of all celiacs in America), and some kind of trigger. The trigger may be environmental (as in overexposure to wheat), situational (perhaps severe emotional stress), physical (such as a pregnancy, an operation), or pathological (a viral infection).
Once thought to be a childhood disease that would be outgrown, recent evidence indicates that it is not uncommon for the symptoms of celiac disease to disappear during late childhood or adolescence, giving the appearance of a cure. Unfortunately, damage still occurs during these years of apparent health, and later in life these celiacs may find they have suffered considerable damage to the small intestine, and have for years deprived themselves of important nutrients.