deletions and inverted duplication chromosomes.

Ideograms and partial karyotypes are shown. For the deletions, the arrows indicate a) the deletion of chromosome 15q11-13 associated with Prader-Willi and Angelman syndromes, and b) the deletion of 22q11.21-11.23 (bottom) associated with DiGeorge and velocardiofacial syndromes. c) For the inverted duplications, the ideograms and partial karyotypes of two chromosome 15s show the two different sizes of inv dup (15) chromosomes. The smaller inv dup (15), on the left, is not associated with phenotypic abnormalities, whereas the larger inv dup (15), on the right, is associated with an abnormal phenotype (the central two are normal chromosome 15). d) The inv dup (22) (right) is associated with the cat eye syndrome.