A
genetic disorder in which the person will
time-travel either into the past or future uncontrollably, leaving everything that is not a part of the human body.
(From
The Time Traveler's Wife, excellent novel may I add.)
Henry is unable to control his
chrono displacement disorder, his time-traveling: when he leaves, where he goes, or how long his trip will last. His destinations are tied to his subconscious, as Henry most often travels to places he has visited or will eventually visit.