A Rare Case of Homozygous δβ-Thalassemia in Childhood: Molecular Diagnosis and Comprehensive Family Analysis

Abstract

Delta- Beta (δβ)-Thalassemia is a rare autosomal recessive hemoglobinopathy caused by deletions in the δ- and β-globin genes, leading to prolonged fetal hemoglobin (HbF) production. δβ-Thalassemia can resemble β-thalassemia major due to anemia and increased HbF. A step-by-step method is required for accurate diagnosis, which includes initial HPLC screening, family hemoglobin studies, and molecular tests. A four-year-old female presented with anemia. Initial HPLC results showed HbF 99.2%, HbA 0.8%, and no HbA₂, indicating a rare hemoglobinopathy. Subsequent family HPLC tests revealed inheritance patterns, but conclusive carrier status was not identified until molecular testing. Molecular investigation verified a homozygous loss of HBB, HBD, and HBG1. Pedigree analysis indicated autosomal recessive inheritance in which both parents and siblings were identified as heterozygous 
carriers. The identification of unique laboratory and molecular features facilitates genetic counselling and family screening, thereby aiding in the prevention of misdiagnosis and the avoidance of unwarranted transfusions.