To the Editor: Jacobson et al. (June 7 issue)1 report on an interesting and provocative case in which the clonality of hematopoietic cells appeared to be maintained even after hematologic remission was achieved in a heterozygote for glucose-6-phosphate dehydrogenase deficiency with acute leukemia. Observations of this type are extremely important and can provide new insights into the pathogenesis of acute leukemia. In an earlier study of a heterozygote for glucose-6-phosphate dehydrogenase type A and Baltimore—Austin, my colleagues and I suggested the possibility that the peripheral-blood cells in a patient with leukemia in remission were part of the leukemic clone.2 We. © 1984, Massachusetts Medical Society. All rights reserved.