Page 225 - Haematologica Atlas of Hematologic Cytology

CHAPTER 26 - Inherited hemolytic anemias
Figure 8 Hereditary elliptocytosis elliptocytosis The hereditary elliptocytosis elliptocytosis syndromes are a a a a heterogeneous group of disor- ders characterized by the presence of elliptical-shaped erythrocytes on peripheral blood smear Clinical manife- stations range from the asymptomatic carrier state to to severe transfusion-dependent hemolytic anemia Here- ditary elliptocytosis occurs worldwide in in in in all racial and and ethnic groups and and is is inherited in in in in an an an an autosomal dominant pattern with an estimated incidence of of 1:2000-4000 individuals It is usually found in in in areas of of endemic malaria (approaching an an an an an an incidence of of 1:100) particularly in in in sub ects of of African and Mediterranean ancestry presumably because elliptocytes confer some resistance to to malaria The true incidence of this disorder is is is is unknown as
many affected patients are asymptomatic The principal defect is mechanical weakness or fragility of the erythrocyte membrane membrane skeleton due to to defects in in in in in in various membrane membrane proteins including - - and and -spectrin protein protein 4 1 and and glycophorin C The The majority of of cases are caused by defects in in in spectrin The The most severe expression of of heredi- tary tary elliptocytosis is is is hereditary pyropoikilocytosis characterized by a a a a a a a a transfusion-dependent hemolytic anemia with onset in in infancy Patients are either compound heterozygotes or or homozygotes for a a a a a missense mutation of / spectrin spectrin Hereditary pyropoikilocytosis may also be due to to to the presence of a a a a a a a spectrin spectrin mutation in in in trans to to to a a a a a a a low-expression -spectrin allele ( el el ) 212