This cluster of papers explores the genetic, clinical, and epidemiological aspects of hemoglobin disorders, including sickle-cell disease and thalassemia. It covers topics such as hemolysis, fetal hemoglobin regulation, iron overload, pulmonary hypertension, and the use of transfusion therapy. The genetic regulation of erythropoiesis by factors like GATA1 and BCL11A is also a focus of several papers.