Hereditary pyropoikilocytosis (HPP) is a rare disorder of the red blood cell membranes related to abnormal structural proteins.


Clinical features:

(1) Other family members are usually affected, often with an autosomal recessive pattern of inheritance.

(2) The patient experiences a hemolytic anemia which may range from mild to severe.

(3) Most patients are Black but the condition may occur in Arabs and Caucasians.


Laboratory findings:

(1) The peripheral blood smear shows microspherocytes, budding erythrocytes, elliptocytes/ovalocytes, schistocytes and filamentous forms.

(2) Testing at various temperatures shows that red blood cells become fragile at lower temperatures (41 to 45°C) than normal erythrocytes (similar changes seen at >= 49°C).

(3) Molecular studies are needed to identify mutations in alpha-spectrin or other structural proteins. Defects may be qualitative or quantitative.


Differential diagnosis:

(1) other forms of hereditary elliptocytosis

(2) DIC or other cause of schistocytosis

(3) thermal burn

(4) artifact caused by overheating the blood sample during transport or handling

(5) sickle cell disease or other form of unstable hemoglobinopathy


To read more or access our algorithms and calculators, please log in or register.