A novel translocation, t(9;11)(q33;q23) involving the HRX gene in an acute monocytic leukemia.

ABSTRACT

A t(9;11)(q33;q23) has been detected by chromosome painting with chromosome 11- and chromosome 9-specific probes in blast cells of a child with acute monocytic leukemia. Using a YAC clone spanning the usual breakpoint region of translocations of acute leukemias, it was shown that the breakpoint was effectively within the same region of the band 11q23. This was confirmed by Southern blot studies that showed the localization of the translocation breakpoint between the 6th and 8th exons of the HRX gene. The implication of the HRX gene in t(9;11)(q33;q23) is a novel example of the diversity of translocations involving this gene in hemopoietic disorders. Sequencing DNA in the vicinity of the breakpoints should help to understand the reason of the localization of the recombination hot spot at band 11q23.