Concomitant inheritance of α‐thalassemia in β°‐thalassemia/hb e disease

Abstract

Concomitant inheritance of α‐thalassemia in patients with β°‐thalassemia/hemoglobin (Hb) E disease was detected by restriction endonuclease DNA mapping. Among 42 patients with β°‐thalassemia/Hb E disease, seven were found to have an α‐thalassemia‐2 haplotype. Of these, five belonged to the rightward or 3.7‐kb type of α‐thalassemia‐2 and the remaining two the leftward or 4.2‐kb type. All the seven patients with α‐thalassemia‐2 haplotype had hemoglobin levels of 7.4 g/dl or above; those without detectable α‐thalassemia had hemoglobin levels both higher and lower than 7.4 g/dI. The latter attended the clinic regularly, the former did occasionally. These findings suggest that concomitant inheritance of α‐thalassemia can alleviate the severity of β°‐thalassemia/Hb E disease. Failure to find α‐thalassemia‐1 haplotype in these patients suggests that concomitant inheritance of α‐thalassemia‐1 with β°‐thalassemia/Hb E might lead to so mild a condition that the individuals do not present clinically. The fact that many patients without a detectable α‐thalassemia haplotype also had hemoglobin levels of 7.4 g/dl or higher suggests that there are additional factors responsible for the mildness of β°‐thalassemia/Hb E disease. Copyright © 1985 Wiley‐Liss, Inc., A Wiley Company