Synthesis of HB Lepore Boston in Peripheral Blood

Two sisters, double heterozygotes for Hb Lepore and β-thalassemia, of Italian origin (Naples), were extensively studied because of their particularly mild clinical and hematological picture, rather unusual in this type of syndrome. Family studies were carried out, and two Hb Lepore heterozygous carriers (the mother and a sister) and two β-thalassemia heterozygotes (the father and a brother) were identified. In vitro biosynthetic studies carried out in both a Hb Lepore carrier and the Hb Lepore/β-thalassemia double heterozygotes indicated an evident incorporation of radioactivity into the chromatographic peak which structural studies demonstrated to be Boston (= Washington) type of δβ-chain (i.e., δ87 Gln β116 His). The amounts of synthesis were roughly of the same order of magnitude as the relative levels of Hb Lepore in the red cell hemolysates, indicating the presence, in the reticulocytes of these subjects, of stable δβ mRNA molecules. These findings provide the opportunity to reconsider the current views indicating the instability of mRNAs as the cause of the low synthetic activity of the δβ and βδ fusion genes.