PARTIAL TRISOMY 1Q, AN UNCOMMON CHROMOSOMAL ABERRATION IN ERYTHROLEUKEMIA

A 2 years 4 months old boy with erythroleukemia (FAB-M6) and Down's sy ndrome is described. Chromosome analysis of bone marrow leukemic blast s revealed apart from the trisomy 21 a partial trisomy of the long arm of chromosome 1:1q23 --> 1qter in all cells and trisomy 8 mosaicism. To the best of our knowledge this is the first time that a partial tri somy of chromosome 1 in association with erythroleukemia has been desc ribed. Previous reports of other hematologic malignancies with aberrat ions of chromosome 1 indicate that the breakpoint 1q23 is nonrandom an d that trisomies of chromosome 1 plays a crucial role in the course of development of hematologic malignancies. This could probably also be true for erythroleukemias.