Diagnosis of DiGeorge and Williams syndromes using FISH analysis of peripheral blood smears

We describe the use of a FISH protocol for detecting chromosome microdeleti ons in peripheral blood smear leukocytes. This method has the advantage of a smaller sample requirement than classical metaphase chromosome analysis a nd the potential for analysis of a larger number of chromosome microdeletio ns using a routine blood smear. A selected series of 10 DiGeorge syndrome ( DCS) and 12 Williams-Beuren syndrome (WBS) patients were correctly diagnose d by this method confirming results obtained by molecular cytogenetic metap hases. These results support effectiveness of interphase FISH analysis on p eripheral blood smears as a focused, single-step method for the detection o f chromosome microdeletions. (C) 1999 Academic Press.