Homozygous delta beta-thalassemia: A rare case report

Abstract

Delta Beta (δβ) thalassemia is a rare autosomal recessive hemoglobinopathy. This is caused by either reduced production of δ and β genes (heterozygous state) or complete absence (homozygous state). High-performance liquid chromatography (HPLC) is an important screening and diagnostic tool, to be supported by molecular data and parental studies. A 40-year-old male (propositus), with mild anemia presented in the outpatient department. There were no other definitive causes of anemia with adequate nutritional status and no response after the treatment with nutritional supplements. HPLC was advised to look for any qualitative/quantitative defects. HPLC findings reveal 96% fetal hemoglobin (HbF), a very small quantity of adult hemoglobin (HbA), and an absent HbA2. In view of this data, followed up with parental studies. Both parents had elevated HbF and similar grades of anemia. These supported the presence of a heterozygous state of δβ-thalassemia in parents and homozygous δβ thalassemia in propositus. In δβ-thalassemia, there is a deletion of the δ and β genes on Chromosome 11. Expression of the gamma gene increases to compensate, causing increased production of gamma globulin for HbF (α2 β2). On HPLC or electrophoresis, heterozygosity shows as normal HbA2 and elevated HbF, and as absent HbA2 with almost 100% HbF for homozygous individuals. Screening of hemoglobinopathies by HPLC is that can be further subjected to parental screening for a more definitive diagnosis and narrow down the differentials as compared to molecular testing considering the cost, limited availability, and higher turnaround time.