DE-NOVO TANDEM DUPLICATION OF CHROMOSOME SEGMENT 22QLL-Q12 - CLINICAL, CYTOGENETIC, AND MOLECULAR CHARACTERIZATION

We report on a case of duplication of the segment 22q11-q12 due to a de novo duplication. Molecular cytogenetics studies demonstrated this to be a tandem duplication, flanked proximally by the marker D22Z4, a centromeric alpha satellite DNA repeat, and distally by D22S260, an anonymous DNA marker proximal to the Ewing sarcoma breakpoint. The segment includes the regions responsible for the ''cat-eye,'' Di George, and velo-cardio-facial syndromes and extends distal to the breakpoint cluster region (BCR). The clinical picture is dominated by the cardiac defects and includes findings reminiscent of ''cat-eye'' syndrome. These findings reinforce the hypothesis that the proximal 22q region contains dosage-sensitive genes involved in development. (C) 1995 Wiley-Liss, Inc.