Chromosome Abnormalities from NHGRI

This is an image of chromosome abnormalities from National Human Genome Research Institute (NHGRI). Most chromosome abnormalities occur as an accident in the egg or sperm. In these cases, the abnormality is present in every cell of the body. Some abnormalities, however, happen after conception; then some cells have the abnormality and some do not. Credit: Darryl Leja and Ernesto del Aguila, NHGRI