DIGEORGE-ANOMALY AND CHROMOSOME 10P DELETIONS - ONE OR 2 LOCI

We report on a patient with DiGeorge syndrome (DGS) phenotype or anoma ly and an unbalanced translocation [45,XY,-10,-22, +der(10),t(10;22)(p 13;q11)] resulting in monosomy of 10p13-pter and 22q11-pter. Because b oth regions involved in this rearrangement have been implicated in DGS , we performed a molecular cytogenetic analysis of both loci in this p atient, Results indicate that the chromosome 22 DGS locus is intact bu t that the terminal deletion of the short arm of chromosome 10 is adja cent to or partially overlapping with the recently defined consensus d eleted region observed in DGS patients with 10p deletions. We conclude that the DGS anomaly in our patient is likely to be due to haploinsuf ficiency of genes located on chromosome 10p. Most, if not all, of the region included in the previously described 10p smallest region of del etion overlap is not deleted in our patient, Therefore, this deletion breakpoint either narrows the previously proposed 10p region or define s a second region within 10p critical for the DGS anomaly. (C) 1997 Wi ley-Liss, Inc.