Abstract
We report a Thai boy with a compound heterozygosity for the α2 polyadenylation signal mutation (AATAAA → AATA– –) and α0-thalassemia (– –SEA), who suffered from Hb H disease with more severe clinical symptoms than those usually observed with deletional Hb H disease. His Hb H level was as high as 52% of total hemoglobin. The hematologic data of this unusual case of Hb H disease was compared with those of Hb H disease with a homozygosity for the α2 polyadenylation signal mutation, and compound heterozygosity of the α2 polyadenylation signal mutation and α0-thalassemia. A simple DNA assay based on an allele specific polymerase chain reaction for the detection of this polyadenylation signal mutation is described.