DETECTION OF SUBMICROSCOPIC CHROMOSOMAL DELETIONS IN ANIRIDIA PATIENTS USING FLUORESCENCE IN-SITU HYBRIDIZATION AND A PANEL OF COSMIDS COVERING THE WT1 GENE

A series of cosmids have been isolated from a human chromosome 11-spec ific cosmid library using the human Wilms tumour predisposition gene c DNA, WT33. Seven overlapping cosmids were isolated which cover the gen omic sequence of WT1 and in situ hybridisation shows that they all loc alise to the p13 region of chromosome 11. Chromosomes from patients wi th aniridia and Wilms tumour, and a small subband deletion in 11p13, w ere analysed and no hybridisation signal was seen on the deletion chro mosomes. These cosmids, therefore, can be used to analyse chromosomes from patients with sporadic aniridia for submicroscopic deletions. Ani ridia patients who show normal hybridisation patterns on both chromoso mes need no longer be screened for Wilms tumours.