MUTATION ANALYSIS OF THE WT1 GENE IN SPORADIC CHILDHOOD LEUKEMIA

The 10 coding exons of the WT1 gene, from 39 bp upstream of the transl ation initiation codon to 12 bp downstream of the stop codon, were exa mined for point mutations in a panel of 48 sporadic childhood acute le ukaemias using the single-stranded conformational polymorphism (SSCP) assay. The panel included 33 cases of acute lymphocytic leukaemia and 15 cases of acute myeloid leukaemia. This is the first study in which sporadic childhood leukaemias have been examined for WT1 point mutatio ns across the entire coding region of the WT1 gene, however, no tumori genic point mutations or small deletions or insertions could be identi fied in these patients. A previously described polymorphism in exon 7, resulting in an A to G transition in an arginine codon, was observed at a frequency of 21.5%, equivalent to that seen in the normal populat ion. This study suggests that point mutations in the coding regions of the WT1 occur infrequently in leukaemias of childhood.