[Myelomonocytic leukemia with Philadelphia-positive and Philadelphia-negative cell lines in early childhood (author's transl)].

The authors report on an infant with myeloproliferative syndrome of the myelomonocytic type. The findings fulfilled the criteria for juvenile chronic myeloid leukemia except that there was no increase of fetal hemoglobulin and no depression of erythrocyte carbonic anhydrase I. In one half of the bone marrow cells a Ph1-chromosome was found. During the course of the disease the Ph1-positive clone was successively replaced by cell lines with different chromosomal aberrations. The relationship between the cytogenetic mosaicism and the clinical and laboratory findings is discussed.