Sickle cell disease: Recent advances

Abstract

Diagnosis The term sickle cell disease encompasses several distinct genetic disorders, the most common of which is sickle cell anemia (homozygous sickle ceil disease or SS disease), which occurs in 1 of 450 black neonates. Somewhat less common are sickle cell-hemoglobin C (SC) disease and sickle cell-p thalassemia (S-p thalassemia, which includes both the p’ and p” variants). Sickle trait (which affects 8% of all African-Americans) is not considered a disease. The diagnosis of these conditions is based on history of disease complications, physical findings (jaundice, pallor, cardiac murmurs, splenomegaly), routine hematologic tests (hemoglobin, mean cell volume, peripheral blood smear), sickle solubility test, and hemoglobin electrophoresis or isoelectric focusing. A major advance during the past decade has been the widespread implementation in most states of neonatal screening programs, which have allowed sickle hemoglobinopathies to be diagnosed at birth and confirmed shortly thereafter. This fosters early education of parents and primary physicians. It also encourages implementation of preventive care practices, such as twice daily oral prophylactic penicillin and instructing parents to palpate the spleen. Neonatal screening programs now exist in