Analysis of Deletional Hb H Diseases in Samples with Hb A2-Hb H and Hb A2-Hb Bart's on Capillary Electrophoresis.

The capillary electrophoresis (CE) system allows the quantification of Hb Bart's (γ4) and Hb H (β4) that is used for screening of Hb H disease. However, Hb Bart's hydrops fetalis and Hb H are not always codetected in patients with Hb H disease. In this study, 35 samples were analyzed for the α0-thalassemia (α0-thal) [- -SEA (Southeast Asian) and - -THAI (Thailand)] deletions and the α+-thal [-α3.7 (rightward) and -α4.2 (leftward)] type deletions using real time-polymerase chain reaction (real time-PCR) with SYBR Green1 and high-resolution melting (HRM) analysis and conventional gap-PCR techniques, respectively. Results showed that 28 of 29 (96.6%) samples with the Hb A2-Hb H phenotype on CE electrophoregrams presented the genotype of - -SEA/-α3.7, while the - -SEA/-α4.2 made up the remainder. The - -SEA/-α3.7 genotype was also found in all six samples (100.0%) with Hb A2-Hb Bart's on CE electrophoregrams. Thus, for genetic counseling, prevention and control programs of Hb Bart's hydrops fetalis and Hb H disease, α-thal genotype analysis is required.