Prevalence of hemoglobin variants and hemoglobinopathies using cation-exchange high-performance liquid chromatography in central reference laboratory of India: A report of 65779 cases

CONTEXT: Hemoglobinopathies constitute the world's most common genetically inherited red blood cell disorder. Screening and accurate identification of hemoglobin (Hb) variants have become increasingly important in antenatal diagnosis and prevention of Hb disorders. AIM: The aim of this study was to screen and identify Hb fractions prevalent in the Central Reference Laboratory of India. MATERIALS AND METHODS: A total of 65,779 cases were screened for hemoglobinopathies on the bio-rad variant high-performance liquid chromatography (HPLC) system by beta-thalassemia short program. The retention times, proportion of the hemoglobin (%) and the peak characteristics for all hemoglobin fractions were recorded. Molecular analysis of the beta-globin gene was carried out by DNA sequencing on eight cases. RESULTS: Total number of abnormal Hb fractions on cation exchange-HPLC (CE-HPLC) was seen in 12,131 (18.44%) cases. Beta-thalassemia trait was the predominant genetic Hb disorder accounting for 7377 cases (11.21%) of the total cases. This was followed by sickle cell trait (2.01%), sickle cell disease (1.59%), beta-thalassemia syndrome (0.80%), HbE trait (0.79%), and borderline HbA(2) (0.51%). Molecular characterization of eight rare cases of hemoglobin variants by beta-globin gene sequencing identified three cases of Hb Beth Israel, two cases of Hb Hofu trait, and one case each of Hb J Cambridge, Hb Mizunami, and Hb Sherwood Forest. CONCLUSION: Superior resolution, rapid assay time, and accurate quantification make CE-HPLC suitable for the routine investigation of hemoglobinopathies.