A Review of Haptoglobin Typing Methods for Disease Association Study and Preventing Anaphylactic Transfusion Reaction

Figure 1

A schematic diagram of the genetic structure of the 𝐻𝑝¹, 𝐻𝑝², and 𝐻𝑝^𝑑𝑒𝑙 alleles. The 𝐻𝑝¹ allele has 5 exons compared to 7 exons of the 𝐻𝑝² allele. Exons 5 and 6 of the 𝐻𝑝² allele are the result of an internal duplication of exon 3 and exon 4 of the 𝐻𝑝¹ allele. A deletion spanning from the upstream region of exon 1 of the Hp gene to intron 4 of the Hpr gene makes the 𝐻𝑝^𝑑𝑒𝑙 allele. The black box and the shaded box represent exons of the Hp gene and the Hpr gene, respectively. The number above each box designates the number of the corresponding exon (see text for details). Hp: haptoglobin gene; Hpr: haptoglobin-related protein.