Complex interaction of Hb Q-Thailand and Hb E with α⁰-thalassemia and hereditary persistence of fetal hemoglobin in a Chinese family

Hemoglobin (Hb) Q-Thailand, Hb E, and other forms of thalassemia are prevalent in Southeast Asia including China. We report a hitherto undescribed condition in which four forms of Hb defects co-segregate. The proband was a 20-year-old Chinese man who presented with moderate hypochromic microcytosis with Hb 73 g/l, hematocrit (Hct) 27.0%, mean corpuscular volume 57.6 fl, mean corpuscular hemoglobin 15.5 pg, and mean corpuscular hemoglobin concentration (MCHC) 268.0 g/l. Both Hb electrophoresis and high-performance liquid chromatography analysis revealed abnormal Hbs. DNA analysis demonstrated that the proband was a double heterozygote of Hb Q-Thailand and Hb E in combination with α⁰-thalassemia and Southeast Asian-type hereditary persistence of fetal hemoglobin (SEA-HPFH). Family study identified that her father was a double heterozygote for Hb Q-Thailand and Hb E, whereas her mother was a heterozygote for SEA-HPFH with α⁰-thalassemia. Moreover, his brother was a classical Hb QH disease patient. The genotype–phenotype relationship observed in this Chinese family with complex thalassemia syndromes is presented. This work will provide some clinical implications for molecular diagnosis for complex hemoglobinopathies.