Hereditary spherocytosis

What it is

Hereditary spherocytosis is a membrane disorder of the red cell, and it sits among the congenital non-immune causes of hemolytic anemia along with hereditary elliptocytosis, hereditary stomatocytosis, hereditary pyropoikilocytosis and hereditary xerocytosis. There is a lack of key red cell cytoskeletal membrane proteins such as spectrin or ankyrin. This lack produces membrane instability that forces the cell to take the smallest volume possible, a sphere. Such cells are quite small, with lack of the central zone of pallor and loss of the biconcave shape; they are the spherocytes, and they do not survive in circulation for as long as normal red cells.

Causes and risk

Inheritance is autosomal dominant in about 75%, and the condition is most frequent in northern Europeans. A family history of anemia is part of the picture.

How it presents

Hemolytic anemia, jaundice and splenomegaly.