Hereditary elliptocytosis

Hereditary elliptocytosis is a blood disorder that runs in families. What changes is the shape of the red blood cell: on a peripheral blood smear, a drop of blood spread on a slide and stained for viewing under the microscope, the cells appear elongated, oval or frankly elliptical instead of round.

A normal red blood cell deforms to get through the narrowest vessels and then springs back into shape. It can do that because of the scaffolding just beneath its membrane, made of proteins such as spectrin, protein 4.1, band 3 and, more rarely, glycophorin C. When a genetic change alters one of them, the cell loses that elastic recoil: without its spring, it keeps the shape of the last squeeze.

The spleen, the organ that inspects and clears worn-out red blood cells, traps and removes these elliptocytes, and that removal is what produces hemolytic anemia, meaning anemia from the destruction of red blood cells. Even so, most people with hereditary elliptocytosis have no symptoms and need no specific treatment.