Double Heterozygosity for Hemoglobin G (α^68Lys₂β^A₂) and Hemoglobin D (α^A₂β^121Gln₂)

An electrophoretic pattern which revealed three major hemoglobin components was found in five members of an Afro-American family. The composition of the hemoglobin resulted from heterozygosity both at the α locus for hemoglobin G_Philadelphia, in which lysine replaces the normal asparagine at the 68th residue and at the β locus for hemoglobin D_Punjab in which glutamine replaces normal glutamic acid at residue 121. The simultaneous presence of these α and β chain variants did not lead to any well defined clinical abnormalities. The pattern of inheritance of hemoglobin variants in this family provided further evidence for independent segregation of the loci responsible for α and β chain synthesis.