Down's syndrome with myelodysplastic syndrome showing t(7;11)(p13;p14).

We report a boy with Down's syndrome (DS) who developed myelodysplastic syndrome (MDS) after spontaneous remission of transient myeloproliferative disorder (TMD) at birth. Chromosomal analysis of the blasts in the MDS phase demonstrated t(7;11)(p13;p14) which had not been detected in the TMD phase. NUP98-HOXA9 chimera mRNA, which is known to be involved in t(7;11)(p15;p15) translocation in acute myeloid leukemia (AML), was not detected by reverse transcriptase-polymerase chain reaction, and NUP98 rearrangement was not detected by Southern blot analysis of the blasts in the MDS phase. Reciprocal translocation is very rare in AML/MDS in DS, and the t(7;11)(p13;p14) found in our patient was different from the recurrent translocation t(7;11)(p15;p15) previously reported. Copyright 2000 Wiley-Liss, Inc.