Mild Beta-Thalassemia intermedia Caused by Compound Heterozygosity for Gγ(Aγδβ)o/β-Thalassemia and Molecular Characterization of the Defect in Four Chinese Families

Molecular characterization of the compound heterozygous condition – G γ( A γδβ) o /β-thalassemia – in four families showing mild β-thalassemia intermedia was carried out using DNA amplification techniques. Using the Amplification Refractory Mutation System (ARMS) to confirm the β-mutations and DNA amplification to detect the 100-kb Chinese-specific G γ( A γδβ) o -deletion, two families were confirmed to possess G γ( A γδβ) o /β-thalassemia with the IVSII No. 654 β + -allele. In the third family, the G γ( A γδβ) o -deletion was confirmed in the father and the mother was a β-thalassemia carrier with the cd 41–42 β o -allele. Their affected child with G γ( A γδβ) o /β-thalassemia was found to be transfusion dependent. The same G γ( A γδβ) o -deletion and β-thalassemia (cd 41–42) was also confirmed in a fourth family. In addition, the mother was also diagnosed with Hb H disease (genotype -α 3.7 /– SEA ). Both the children were found to possess G γ( A γδβ) o /β-thalassemia but they were not transfusion dependent and this could be due to co-inheritance of α-thalassemia-2 (genotype-α 3.7 /αα) in the children together with their compound heterozygous condition.