Unusual translocations involving chromosomes 12;22 and 9;12 in a case of chronic myelogenous leukemia.

A case of chronic myelogenous leukemia (CML) with highly unusual translocations involving both chromosomes #12 is reported. The origin of the Ph1 chromosome was due to a 12p/22q translocation. Chromosome #9 was involved in a translocation with the other chromosome #12. By critical examination of the "size" of the Philadelphia chromosome, it was noted that the breakpoints on 22q were different when compared with a previous case (see Verma and Dosik [16]), although the short arm of chromosome #12 (12p) was involved in both instances. So far, no apparent differences in the course of the disease have been attributed to the types of translocation observed in these cases.