Profile of Hemoglobin D Trait in West Bengal, India

Implications of Population Screening for Thalassemias and Hemoglobinopathies in Rural Areas of West Bengal, India: Report of a 10-Year Study of 287,258 Cases

Thalassemia and hemoglobinopathies are the most common cause of high morbidity and mortality in India. Detection of carriers and premarital counseling play an important role in preventing the birth of a thalassemic child. The present study aimed to detect large numbers of asymptomatic carriers in rural areas of West Bengal, India. The present cross-sectional study was conducted over a period of 10 years. Thalassemia awareness programs and detection camps were organized at the community level. After signed written consent was obtained, the collected blood samples were subjected to a complete blood count (CBC) in an automated blood cell counter and then analyzed by high performance liquid chromatography (HPLC); in difficult cases, samples were sent to the reference laboratory for molecular characterization. Out of 287,258 samples collected, 32,921 (11.46%) cases revealed abnormal hemoglobins (Hbs); of these, 31,782 (11.06%) carried heterozygous states (carriers/traits), and the remainder were either homozygous or compound heterozygous for different hemoglobinopathies. Two common variants were revealed in the study, namely β-thalassemia (β-thal) (7.23%) and Hb E [β26(B8)Glu→Lys, HBB: c.79G>A] (2.77%) traits. Among homozygous or compound heterozygous states, Hb E/β-thal (0.14%) and β-thal major (β-TM) (0.12%) were predominant. In rural areas of West Bengal, the most common Hb variants detected were β-thal and Hb E traits. In view of the high prevalence of hemoglobinopathies in this region, routine premarital screening and genetic counseling should be emphasized and encouraged to prevent the birth of a thalassemic child, and thus curtailing the burden on families and the health economy.

Compound Heterozygosity for Hb D-Ibadan (HBB: c.263C>A) and Hb C (HBB: c.19G>A)

We report an individual with a compound heterozygosity for Hb D-Ibadan (HBB: c.263C>A) and Hb C (HBB: c.19G>A), a hemoglobin (Hb) combination not previously identified. The compound hemoglobinopathy was detected in a young woman during routine prenatal screening. Variant Hbs were identified and confirmed by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) followed by Sanger DNA sequencing. Hb D-Ibadan was present in significant excess over Hb C (70.3 to 24.4%). A complete blood count (CBC) revealed moderate microcytosis with slight anemia. The history suggests the Hb combination is clinically silent. The findings indicate the compound hemoglobinopathy demonstrates thalassemia minor-like red cell indices with an unequal distribution of the variant Hbs. Comparison with other Hb D-like heterozygous conditions is reviewed.