Exon 9 mutations in the WT1 gene, without influencing KTS splice isoforms,are also responsible for Frasier syndrome

We report new mutations in exon 9 of the WT1 gene that did not alter the ra tio of +/- KTS splice isoforms in two unrelated patients with Frasier syndr ome (FS). The mutation of intron 9 inducing defective alternative splicing was reported to be responsible for this syndrome. The mutations found in ou r cases occurred in the same exon of the WT1 gene as detected in Denys-Dras h syndrome (DDS) and could not be explained by the previously proposed mech anism. The results suggest that the two syndromes originate from the same W T1 gene abnormality. From a molecular biological point of view, we conclude d that the two diseases were not separable, and that FS should be included as an atypical form of DDS. Hum Mutat 14:466-470, 1999. (C) 1999 Wiley-Liss , Inc.