d+-Thalassemia in Sardinia

Abstract

We have defined a new type of d-thalassemia in which d-globin chain synthesis is incompletely suppressed. Homozygotes have unusually low HbA2 levels, and double heterozygosity for this d-thalassemia gene and ß-thalassemia normalizes the HbA2 level. The d-thalassemia occurs on a chromosome that is identifiable using polymorphic restriction endonuclease sites. We call this condition d+-thalassemia, to distinguish it from the previously described d0-thalassemia syndromes in which no d-globin chain synthesis occurs.