Hemoglobin analysis for prenatal diagnosis of severe thalassemia diseases using low pressure liquid chromatography

Abstract

Fetal hemoglobin (Hb) analysis is an alternative method to DNA analysis for prenatal diagnosis of severe thalassemia diseases. Therefore in this study, fetal Hb patterns determined using low pressure liquid chromatography (LPLC) based Hb analyzer were analyzed. Study was done on 74 fetal blood specimens obtained for prenatal diagnosis of severe thalassemia diseases at the Centre for Research and Development of Medical Diagnostic Laboratories. Globin genotypes were defined by DNA analysis using PCR and related techniques. Among 74 fetuses, there were 11 normal fetuses, 23 cases of α - thalassemia (with 8 genotypes), 29 cases with β - thalassemia and / or Hb E (with 4 genotypes) and 11 cases of Hb E / α - thalassemia (7 genotypes). Normal fetuses presented with Hb F (88.1 + 5.3 %) and Hb A (6.6 + 2.9 %). In 15 cases with homozygous a-thalassemia 1, only Hb Bart’s (99.0 + 1.7 %) with no Hb F and Hb A was observed. In α - thalassemia fetuses, it was found that Hb Bart’s levels depended on the number of α -globin gene defect. In 11 cases with β⁰- thalassemia / Hb E disease, only Hb E (1.1 + 0.2 % ) and Hb F (95.2 + 1.1 %) without Hb A were detected. The same pattern was found with homozygous Hb E fetus. These results demonstrate that fetal blood analysis using LPLC can be used for accurate prenatal diagnosis of homozygous α -thalassemia 1. The test can also be applied to prenatal diagnosis of β⁰ -thalassemia / Hb E disease although in some cases differential diagnosis with homozygous Hb E would require further DNA testing.

Keywords: Hemoglobin analysis, Fetal blood, LPLC, Prenatal diagnosis, Thalassemia