α-thalassemia among pediatric hemoglobin S homozygotes : molecular and clinical studies

Abstract

The variability of α globin gene numbers due to a+-thalassemia (a+-th or -α) is the most common molecular difference that influences the hematological and clinical expression of homozygous hemoglobin S(SS). The occurrence of a+-th among adult SS patients results in decreased hemolysis and increased hemoglobin (Hb) levels. Consequently, longevity is improved but infarctive disease in bone and other organs is deteriorated.' Recent data have shown that the interaction of a+-th and SS is also developmentally regulated. Our studies have sought to establish the effects of α-th on the expression of SS in the course of postnatal development and growth of neonates, infants, and young children. The data obtained thus far indicate a critical role for the spleen in modulating the effects of a+-th from one type of interaction through fetal hemoglobin (HbF) in early childhood, to another type through the mean corpuscular hemoglobin concentration (MCHC) in older children, adolescents and adults. Details of methodology are given in Reference 3.