Pharmacological and molecular approaches for the treatment of β-hemoglobin disorders.

β-hemoglobin disorders, such as β-thalassemia and sickle cell anemia are among the most prevalent inherited genetic disorders worldwide. These disorders are caused by mutations in the gene encoding hemoglobin-β (HBB), a vital protein found in red blood cells (RBCs) that carries oxygen from lungs to all parts of the human body. As a consequence, there has been an enduring interest in this field in formulating therapeutic strategies for the treatment of these diseases. Currently, there is no cure available for hemoglobin disorders, although, some patients have been treated with bone marrow transplantation, whose scope is limited because of the difficulty in finding a histocompatible donor and also due to transplant-associated clinical complications that can arise during the treatment. On account of these constraints, reactivation of fetal hemoglobin (HbF) synthesis holds immense promise and is a viable strategy to alleviate the symptoms of β-hemoglobin disorders. Development of new genomic tools has led to the identification of important natural genetic modifiers of hemoglobin switching which include BCL11A, KLF1, HBSIL-MYB, LRF, LSD1, LDB1, histone deacetylases 1 and 2 (HDAC1 and HDAC2). miRNAs are also promising therapeutic targets for development of more effective strategies for the induction of HbF production. Many new small molecule pharmacological inducers of HbF production are already under pre-clinical and clinical development. Furthermore, recent advancements in gene and cell therapy includes targeted genome editing and iPS cell technologies, both of which utilizes a patient's own cells, are emerging as extremely promising approaches for significantly reducing the burden of β-hemoglobin disorders.