A Rare Super-Unstable Hemoglobin Variant, Hb Monroe [β30(B12)Arg→Thr], Found in Two Myanmar Children
During the making of a precise molecular diagnosis of blood from transfusion dependent anemic patients in the Union of Myanmar by the PCR-sequencing technique, we encountered two Myanmar children (My-194 and My-201) with a rare abnormal hemoglobin, Hb Monroe [β30(B12)Arg→Thr], which causes β0-thalassemia due to missplicing in the course of mRNA processing. One of the children, My-194, was a compound heterozygote for Hb Monroe and a thalassemia mutation of βIVS I-5 G→C, who had a condition of severe β+-thalassemia resembling a β0-thalassemia, while the other, My-201, a homozygote for Hb Monroe. However, Hb analyses of My-194 with IEF and DEAE-HPLC revealed a normal pattern, suggesting that it may be due to blood transfusion. Hb analyses of My-201 showed the presence of Hb A to be about 0% , with Hb F being the main Hb component, suggesting that in this case Hb F instead of Hb A may be produced as the main Hb.