BCL11A and sickle cell disease: Research has established that dysfunctions in TR2/TR4 are implicated in β-thalassemia and sickle cell disease (SCD): β-thalassemia is associated with the defective silencing of γ-globin genes, while in SCD, TR2/TR4 antagonizes BCL11A to reactivate fetal hemoglobin (HbF) expression.