Clinical and Hematological Evaluation of two δ⁰ δ⁰ - Thalassemia Homozygotes

Abstract

Two homozygous δ⁰ β⁰-thalassemia patients, one with the ^Gγ^Aγ type and the other with the ^Gγ type, and their heterozygous parents are described. Red cell indices among the heterozygotes with the ^Gγ^Aγ type of δ⁰β⁰-thalassemia were markedly different from those in heterozygotes with the ^Gγ type. However, the imbalance in in vitro hemoglobin synthesis was quite similar in the two heterozygous conditions. The same was observed for the homozygous patients; the in vitro chain synthesis was severely imbalanced as seen in β-thalassemia major. The clinical and some of the hematological findings were milder in the ^Gγ-δ⁰ β⁰-thalassemia homozygote than in the ^Gγ^Aγ - δ⁰ β⁰-thalassemia homozygote. The death of a sibling of the ^Gγ - δ⁰ β⁰-thalassemia homozygote with a diagnosis of thalassemia major suggests that both types of δ⁰ β⁰ -thalassemia could follow a severe clinical and hematological course. The discovery of the ^Gγ type of δ⁰ β⁰-thalassemia in a Turkish child shows that two types of δ⁰ β⁰ - thalassemia can be found in that country. Differentiation between the two types can only be made through structural analyses of Hb F.