The search for hemizygosity at 22qll in patients with isolated cleft palate.

The striking association between oral clefting and the velocardio-facial syndrome (VCFS), a common disorder pathogenetically related to 22q11 deficiency, has prompted the search for this deletion in a group of patients with isolated cleft palate. (CP). Thirty-three patients with posterior CP and 5 with complete CP were included in this study, together with 12 patients with a clinical diagnosis of VCFS. Standard and high resolution chromosome analysis was performed, providing normal results. Southern blotting followed by densitometric analysis and fluorescent in situ hydridization of region 22q11 showed no single case of deletion among the isolated CP patients, while deficiency was found in 10 of 12 VCFS patients. These results demonstrate that hemizygosity at 22q11 is not increased in isolated CP.