Schematic diagram of the erythrocyte membrane. Schematic diagram of the erythrocyte membrane. The upper portion represents the erythrocyte’s external surface, separated from the internal structures by the lipid bilayer. Proteins shown where mutations result in HS include band 3, ankyrin-1, α-spectrin, β-spectrin, and protein 4.2. (Reprinted with permission from Gallagher PG. Abnormalities of the erythrocyte membrane. Pediatr Clin North Am. 2013;60(6):1358). Robert D. Christensen et al. Pediatrics 2015;135:1107-1114 ©2015 by American Academy of Pediatrics