α‐thalassemia carrier identification by DNA analysis in the screening for thalassemia

Abstract

Differentiation between heterozygous α-thalassemia and several phenotypically resembling alleles at the β-globin gene cluster such as coinherited δ- and β-thalassemia or γδβ-thalassemia is a critical step in genetic counseling. In this paper we report our experience in the identification of the α-thalassemia carrier state using polymerase chain reaction (PCR)-based methods, and the feasibility and simplification of screening for thalassemia using this approach. α-Globin genotype was determined by PCR-based method in 526 adult subjects with reduced mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), normal hemoglobin A2 and F, and normal serum iron. To verify the reliability of the protocol used, in 68 of these subjects we performed globin chain synthesis analysis and in 101 we determined α-globin genotype by Southern blot analysis. Five hundred twenty-one (99%) of 526 subjects examined were identified as carriers of one or two α-thalassemia alleles. The identification of the α-thalassemia carrier state may be fast and accurate by PCR-based method, avoiding other cumbersome and expensive methods such as globin chain synthesis and Southern blot analysis. Am. J. Hematol. 59:273–278, 1998. © 1998 Wiley-Liss, Inc.