Complex Interaction of Hb Q-Thailand with α and β Thalassemia in a Hakka Family

Abstract Background HbQ-Thailand is an α-globin chain variant that results from a point mutation at codon 74 of the α1-globin gene on chromosome 16p. It commonly appears with a leftward single α-globin gene deletion (-α 4.2 ). There have been few reports regarding the interaction between HbQ-Thailand and other globin gene disorders. Here we found and diagnosed it in the Hakka population of the Fujian Province, China. The study provides an important reference for the clinic diagnose and genetic counseling of thalassemia and hemoglobin diseases. Methods Fresh peripheral blood samples were collected from the proband and her family members testing hematological parameters, hemoglobin components, thalassemia gene, and hemoglobin variants. Results The proband (II1) and her sister (II5) manifested in the obvious microcytic hypochromic anaemia. The CE electropherogram of II1 showed an abnormal band in the migration time at 185 s, which was confirmed as HbQ-Thailand. Another exception band appeared at 250 s of migration time and was proved to be HbE by sequence analysis method. The CE electropherogram of I1 and II3 showed an anomalous band HbE. The mother of the proband (I2) and the III4 and III5 of the family members showed a HbQ-Thailand. The gene results showed that the father (I1) also carried α- and β-thalassemia genes. His genotype was -- SEA and β codons26 ; -- SEA was inherited to II1, II 3, II5, III 1, and III2, and β codons26 was inherited to II1 and II3. The mother (I2) carries the -α 4.2 gene, which was inherited to II1, II5, III4, and III5. Conclusion It was complex to diagnose when the thalassemia combined with several abnormal haemoglobin disorders, and we may use various methods to mutual confirmation. Here we found and diagnosed a rare hemoglobin disease in the Hakka population of the Fujian Province. The study provides an important reference for the clinic diagnose and genetic counseling.