A novel basis for delta beta-thalassemia in a Chinese family
GF Atweh, DE Zhu and BG Forget
We have studied a Chinese family in which beta-thalassemia and delta
beta-thalassemia were found in simple and compound heterozygous states. The
delta beta-thalassemia heterozygote (the mother) had 22.3% hemoglobin F, of
which 40% was G gamma and 60% A gamma; globin chain studies showed an
alpha/beta + gamma ratio of 1.36. The compound heterozygote for delta
beta-thalassemia and beta-thalassemia (the child) had the clinical picture
of thalassemia intermedia and an alpha/beta + gamma ratio of 4.44. Gene
mapping studies were performed using DNA from the affected child. Seventy
kilobases of DNA in the beta- globin gene cluster starting upstream from
the epsilon-globin gene and ending downstream from the beta-globin gene
were mapped, and no detectable deletions or rearrangements were detected.
In addition, heterozygosity was detected at multiple polymorphic
restriction sites in and 3' to the beta-globin gene, which excludes the
possibility of a deletion of the entire beta-globin gene cluster. This is
the first example of a nondeletion delta beta-thalassemia associated with
increased expression of both G gamma and A gamma genes.
Volume 68,
Issue 5,
pp. 1108-1113,
11/01/1986
Copyright © 1986 by The American Society of Hematology
