A CASE OF MYELODYSPLASIA WITH EOSINOPHILIA HAVING A TRANSLOCATION T(512)(Q31Q13) RESTRICTED TO MYELOID CELLS BUT NOT INVOLVING EOSINOPHILS

A chromosomally abnormal clone characterized by a translocation, t(5;1 2)(q31;q13), was detected in the marrow of a child with myelodysplasia and associated eosinophilia which included a generalized skin infiltr ation, Combined immunophenotyping and fluorescence in situ hybridizati on on interphase bone marrow cells showed that the chromosomal rearran gement was restricted to the granulocyte lineage but was not present i n the eosinophils. If the chromosome rearrangement is important in the overproduction of eosinophils in this case, the lineage restriction f ound suggests that its effect must be indirect.