Pleiotropic consequences of the HbS mutation in beta globin gene

Pleiotropy occurs when variation at a single gene locus affects multiple aspects of the phenotype. For persons with an HbS / HBs genotypes, medical consequences include anemia, damage to various internal organs including the spleen and heart, and a "tower" or "bossed skull"

Figure © 1997 by Klug & Cummings; all text material © 2014 by Steven M. Carr