There is a range of genomic aberrations from aneuploidy down to single base pair deletions or inserts. Present technology uses microscopic cytogenetics for detection of large rearrangements (> 2 Mb) and molecular techniques for small rearrangements (< 2 Mb) . There is a gap in practical diagnostic technology in that microscopic cytogenetics has poor sensitivity for aberrations < 5 Mb and the molecular techniques are cumbersome for clinical use in the megabase range. In many cases it is possible to determine that an aberration is present by microscopic cytogenetics but cannot be characterized. We propose to use Spectral Karyotyping (SKY) and supplementary FISH and molecular techniques to characterize these aberrations. Subjects will be seen in the NIH clinical center for a clinical genetics evaluation and phlebotomy for SKY. Confirmation of SKY results will be performed by standard FISH, genomic content mapping, and other standard techniques.