Complex Chromosomal Rearrangements

RJ McKinlay Gardner, David J Amor

Oxford University Press | Published : 2018


Complex chromosome rearrangements (CCRs) include most of the rearrangements that would not be accounted for as “straightforward” classical categories. They may be translocations with three or more segments involved; or they may comprise a mix of translocation and, for example, inversion. Some can be extraordinarily complex. CCRs are classified as types I–IV, most falling into the “least complex” type I category, while types II–IV are grouped as “exceptional CCRs.” Many unbalanced CCRs have arisen de novo and imply no increased reproductive risk. The identification of the clinically normal balanced CCR carrier is less frequent, and for these people, the reproductive risks can be very high.