A complex translocation (5;7) in a patient with acute nonlymphocytic leukemia evolved from a myelodysplastic syndrome.

Complete or partial monosomy for the long arms of chromosomes 5 or 7 or both is frequently observed in therapy-related myelodysplastic syndromes and acute nonlymphocytic leukemia. Sporadic cases have been reported in which partial monosomy is due to unbalanced translocations. The patient described herein carries one such rearrangement. 46,XY,t(1;2) (q32;p23),del(5)(q13),der(7)(5qter-->5q22::7p15-->7 q21:),del(12)(p12), resulting in partial monosomy for the long arms of chromosomes 5 and 7 and in partial monosomy for the short arm of chromosome 7.