[E2A gene in t(1;19)-ALL].

The t(1;19)(q23;p13) seen in approximately 5% of childhood acute lymphoblastic leukemia (ALL) has been reported to be associated with leukoencephalopathy. 1;19 translocation can alter the E2A gene, leading to formation of a chimeric E2A-PBX1 gene that retain the activator domain of the E2A gene but substitute a homeobox domain of the PBX1 gene for the helix-loop-helix DNA binding and dimerization domain of E2A. The translocation breakpoints occurs within a single intron of the E2A gene on chromosome 19, and interrupts a homeobox gene, PBX1, on chromosome 1q23. Most cases with t(1;19) have been identified to have rearranged band of E2A by Southern blotting analysis, and to contain identical E2A-PBX1 chimeric transcripts by use of polymerase chain reaction assay. The molecular breakpoints in pre-B cases differ from those in early pre-B cases among t(1;19)-ALL. Thus, molecular analysis is useful for detection of t(1;19)-ALL.