Homozygous beta-thalassemia without anemia
S Safaya, RF Rieder, CE Dowling, HH Kazazian and JG Adams
State University of New York Health Science Center, Brooklyn 11203.
A 37-year-old man of Guyanese origin was found to have homozygous beta-
thalassemia without anemia. There were no physical stigmata of thalassemia.
The hematocrit value was 41 to 45.8, the mean corpuscular volume was 61 fL,
and the mean corpuscular hemoglobin was 18.9 pg. The HbF was 45% with a G
gamma:A gamma ratio of 3:1. An acid elution preparation of the peripheral
blood showed heterogeneous distribution of HbF, but all erythrocytes
stained for fetal hemoglobin. The beta/alpha synthesis ratio in the
peripheral blood was 0.25; the (beta + gamma)/alpha ratio was 0.55.
Haplotype analysis revealed homozygosity for the -+-+ + + + pattern
(Senegal, type IX) at seven polymorphic restriction sites within the
beta-like gene complex. Digestion of DNA with Xmnl indicated that the -158
C-to-T transition was present in both beta-globin gene clusters. Oligomer
hybridization analysis demonstrated homozygosity for the -29 A-to-G
mutation in the beta-globin promoter region. Although this form of
thalassemia can cause transfusion- requiring anemia, the high-HbF, high-G
gamma phenotype associated with the linked +-+ + subhaplotype and -158
C-to-T substitution appears to have ameliorated the disease in this
subject.
Volume 73,
Issue 1,
pp. 324-328,
01/01/1989
Copyright © 1989 by The American Society of Hematology
