Hemoglobin alpha chain deficiency in black children with variable quantities of hemoglobin Bart's at birth.

Hematologic and globin chain synthesis studies have been made in 21 children, aged 2 to 6 years, many of their parents, and several normal adults and alpha-thalassemia heterozygotes. At birth, 11 children had about 5% hemoglobin (Hb) Bart's, 5 had about 2% Hb Bart's, and 5 had no trace of Hb Bart's. A significant decrease in mean corpuscular volume. (MCV) and mean corpuscular hemoglobin (MCH) values and an increase in the beta/alpha ratio was observed in the first group; microcytosis and hypochromia were absent in the children of the second group although the beta/alpha ratio was significantly increased. The alpha chain deficiency is familial. Increased alpha/alpha ratios were present in many parents although only two parents of children with 5% Hb Bart's at birth had hematologic findings suggestive of the presence of the same type of defect as observed in the children with the larger amount of Hb Bart's at birth.