Hb H disease caused by a homozygosity for the AATAAA → AATAAG mutation in the polyadenylation site of the α2-globin gene: Hematological observations

We have identified 7 patients with Hb H disease as homozygotes for a mutation in the polyadenylation site (AATAA4 → AATAAG) and have compared their hematological data with those of Hb H patients having other types of ct-thalas-semia determinants. All 7 patients exhibited moderate anemia with microcyto-sis and hypochromia being similar to that observed in the other patients. Relatives with a heterozygosity for this mutation are borderline microcytic and hypochromic without a significant anemia but with a low in vitro α/β chain synthesis ratio. Analyses of the hemoglobin components identified low levels of Hb A2 and Hb H that were comparable to those found in other patients with Hb H disease; the level of the ζ chain was low (average 0.14%). © 1992 S. Karger AG, Basel.