The hallmark of β-thalassemia is thought to be ineffective erythropoiesis, which can be caused by a variety of internal and external factors. Several proteins including GATA-1, FoxO3 and pRb are involved in the regulation of normal erythropoiesis to produce functional RBCs and dysregulation of these proteins are reported to be one of the several causes of inefficient erythropoiesis, hemoglobinopathies, or leukemic transformation in hematological illnesses. The aim of this study is to evaluate the expression profiles of GATA-1, FoxO3 and pRb in β-thalassemia major patients in comparison to healthy controls. The present study also aimed to evaluate the longevity associated FoxO3 (rs2802292) polymorphisms in β-thalassemia major patients in Karachi, Pakistan. The reported study was a case control study for which 50 Healthy and 50 β-thalassemia major patients were enrolled after informed consent. The expression analysis of GATA-1, FoxO3 and pRb was done using RT-qPCR and 2 –∆∆Ct method was used to calculate relative quantification of the target genes. FoxO3 polymorphism (rs2802292) was genotyped using ARMS-PCR. The distribution of blood groups in β-thalassemia major patients was observed to be O>B>A. A decrease in BMI with an increase of the ages in the β-thalassemia major patents was also observed as part of the study. When assessing FoxO3 polymorphism rs2802292 (G/T), only 2% of the healthy individuals and no β-thalassemia major patients carrying the allele G. 98% of the study cohort showed homozygosity towards allele T. Expression analysis showed a downregulation of all three studied markers GATA-1, FoxO3 and pRb in β-thalassemia patients. This study indicates the dysregulation of crucial erythropoiesis markers GATA-1, FoxO3 and pRb as an important cause of impaired erythropoiesis in β-thalassemia major patents. Furthermore, a homozygous mutation toward TT allele in FoxO3 rs2802290 anticipates an equally high risk of developing cardiovascular diseases, cancers, and diabetes in our population regardless of experiencing hematological disorders.

Keywords: β-thalassemia, ineffective erythropoiesis, GATA-1, FoxO3, pRb, expression analysis.