MOLECULAR ANALYSIS OF ANIRIDIA PATIENTS FOR DELETIONS INVOLVING THE WILMS-TUMOR GENE

A human aniridia candidate (AN) gene on chromosome 11p13 has been clon ed and characterized. The AN gene is the second cloned gene of the con tiguous genes syndrome WAGR (Wilms' tumor, aniridia, genitourinary mal formations, mental retardation) on chromosome 11p13, WT1 being the fir st gene cloned. Knowledge about the position of the AN and WT1 genes o n the map of 11p13 makes the risk assessment for Wilms' tumor developm ent in AN patients possible. In this study, we analyzed familial and s poradic aniridia patients for deletions in 11p13 by cytogenetic analys es, in situ hybridization, and pulsed field gel electrophoresis (PFGE) . Cytogenetically visible deletions were found in 3/11 sporadic AN cas es and in one AN/WT patient, and submicroscopic deletions were identif ied in two sporadic AN/WT patients and in 1/9 AN families. The exact e xtent of the deletions was determined with PFGE and, as a result, we c ould delineate the risk for Wilms' tumor development. Future analyses of specific deletion endpoints in individual AN cases with the 11p13 d eletion should result in a more precise risk assessment for these pati ents.