inversion

inversion /invur′zhən/ [L, invertere, to turn over] , 1. an abnormal condition in which an organ is turned inside out, such as a uterine inversion. 2. a chromosomal defect in which a segment of a chromosome breaks off and then reattaches to the chromosome in the reverse orientation, causing the genes carried on that part of the chromosome to be in an abnormal position and sequence.