34. Inherited Disorders of Hemoglobin

Abstract

As hemoglobinopathies become more globally widespread, and as technology enables patients to live longer, the burden these diseases place on health care structures around the globe grows in magnitude. Hemoglobin disorders include (1) structural hemoglobin variants, which cause sickle cell disease and (2) thalassemias, resulting from defective globin production and appearing in several different forms. Both types of disorders seemingly developed as a form of carrier resistance against malaria, and as such are widespread in areas profoundly affected by malaria, predominantly Africa, Southeast Asia, the Mediterranean, and the Middle East.

Thalassemias typically require intermittent or complication–based blood transfusions. The most severe types are fatal without life–long monthly transfusions as well as chelating to prevent iron accumulation. Sickle cell anemia, while presenting a high survival rate for patients, can also trigger painful crises during which patients experience acute bone pain due to the "sickling" of oxygen–deprived red blood, which can then block small blood vessels. During these episodes, patients require immediate hospital treatment, including oxygen and palliative care. Over time, chronic complications may arise.

Both severe thalassemia and sickle cell anemia can be prevented by a combination of genetic counseling, prospective carrier screening, and prenatal diagnosis, and can be treated with high–quality patient care, including transfusion, along with bone marrow transplants when possible. Sickle cell mortality can be reduced by the administration of prophylactic penicillin from birth when possible or upon diagnosis. Besides economic accessibility, cultural and religious views must be figured into discussions among governments, communities, and health care providers concerning control of these disorders, particularly through counseling, screening, and termination of affected pregnancies.