Structural Chromosome Aberrations

Structural chromosome aberrations or chromosome mutations represent apart from aneuploidies the most frequent pathologic findings in applied chromosome diagnostics. But they also occur as combinations of both types as in unstable rearrangements or in chaotic karyotypes of early stages of embryonic development. Depending on the indication for chromosome analysis—child with developmental retardation, spontaneous abortions, sterility—the majority of aberrant karyotypes will be unbalanced or balanced. Furthermore, it could be shown that the frequency of de novo and familial aberrations is depending on the type of the aberration. Chromosome mutations are divided into intrachromosomal and interchromosomal aberrations. In addition, complex chromosome rearrangements (CCR) represent a special group of abnormalities, where intrachromosomal and interchromosomal aberrations can be combined in one genome. Their investigation affords the combination of chromosome analyses, microarray and FISH and their characterisation is still under development. In the following intrachromosomal aberrations are shown first, followed by the interchromosomal aberrations.