Detection of Sickle a- or $#{176}-Thalassemia by Studies of Globin Biosynthesis

Globin synthesis studies are useful in the analysis of thalassemia syndromes. We have applied globin synthesis and free a-chain pool studies of peripheral blood to characterize hematologic disorders where aor thalassemia was present in combination with HbS or HbC. In 60 nonthalassemic controls, the $/a specific activity ratio was 1.O ± 0.06 (SD). In three patients with HbS-fi#{176}-thalassemia, the ( + ‘y)/a ratios were 0.48-0.67. In four atients with HbSS-a-thalassemia, the Ia ratio was 1.26 ± 0.18 (1.131.53). The radioactive free a-chain pool in three patients with HbS-fi#{176}-thalassemig was elevated (35.1%-53.0%), while three patients with HbSS-a-thalassemia had decreased free radioactive a-chain pools (3.2%-6.4%); both were significantly different from the mean ( 1 5 .1 % ± 2.6%) of the 1 7 iron-sufficient controls. Simultaneous studies of the fraction of newly synthesized a chain contained in the free a-chain pool in peripheral blood and bone marrow demonstrated that this fraction was larger in peripheral blood than in marrow, and that the differences between thalassemia patients and controls previously found in bone marrow using these methods were also present in peripheral blood. The results indicate that even when family studies are not possible, patients with HbS in combination with aor 1#{176}-thalassemia can be differentiated from those with homozygous sickle cell disease by globin synthesis and free a-chain pool studies using peripheral blood.