Velo-cardio-facial syndrome: frequency and extent of 22q11 deletions

Velo-cardio-facial (VCFS) or Shprintzen syndrome is associated with deletions in a region of chromosome 22q11.2 also deleted in DiGeorge anomaly and some forms of congenital heart disease. Due to the variability of phenotype, the evaluation of the incidence of deletions has been hampered by uncertainty of diagnosis. In this study, 54 patients were diagnosed with VCFS by a single group of clinicians using homogeneous clinical criteria independent of the deletion status. Cell lines of these patients were established and the deletion status evaluated for three loci within the commonly deleted region at 22q11.2 using fluorescence in situ hybridization (FISH). In 81% of the patients all three loci were hemizygous. In one patient we observed a smaller interstitial deletion than that defined by the three loci. The phenotype of this patient was not different from that observed in patients with larger deletions.