HBA2 and thalassemia: In southern China, the most prevalent variants of α-thalassemia are -α3.7 deletion, --SEA deletion, -α4.2 deletion, HBA2 c.369C>G, and HBA2 c.427T>C, while those of β-thalassemia are HBB c.126_129delCTTT, HBB c.52A>T, HBB c.316-197C>T, HBB c.-78A>G, and HBB c.79G>A [35, 36].