Detection of chromosomal aberrations by a whole-genome microsatellite screen

Chromosomal aberrations are a common cause of multiple anomaly syndromes th at include developmental and growth retardation. Current microscopic techni ques are useful for the detection of such aberrations but have a limit of r esolution that is above the threshold for phenotypic effect. We hypothesize d that a genomewide microsatellite screen could detect chromosomal aberrati ons that were not detected by standard cytogenetic techniques in a portion of these individuals. To test this hypothesis, we performed a genomewide mi crosatellite screen of patients, by use of a currently available genetic-ma rker panel that was originally designed for meiotic mapping of Mendelian tr aits. We genotyped similar to 400 markers on 17 pairs of parents and their children who had normal karyotypes. By using this approach, we detected and confirmed two cases of segmental aneusomy among 11 children with multiple congenital anomalies. These data demonstrate that a genomewide microsatelli te scan can be used to detect chromosomal aberrations that are not detected by microscopic techniques.