49 Hereditary Elliptocytosis & Related Variants
Michelle To and Valentin Villatoro
Hereditary Elliptocytosis
Images of hereditary elliptocytosis peripheral blood smears showing numerous elliptocytes. From MLS Collection, University of Alberta.
Image 1: 100x oil immersion. https://doi.org/10.7939/R3F18SW6B
Image 2: 100x oil immersion. https://doi.org/10.7939/R3JS9HQ0S
Hereditary elliptocytosis encompasses group of hereditary conditions that result in the formation of elliptocytes with a decreased erythrocyte lifespan.1 Variants of hereditary elliptocytosis include Hereditary pyropoikilocytosis and Southeast Asian Ovalocytosis.
Mutation:
Genetic mutations involving the horizontal protein linkages between the membrane and cytoskeleton: α-spectrin, β-spectrin, protein 4.1, glycophorin C).2-4 These mutations result in a decreased red blood cell lifespan and increased susceptibility to hemolysis (primarily extravascular). Hemolysis is often mild.
Inheritance:1,3,4
Autosomal dominant
Clinical Features:
Patients are usually asymptomatic and discovery of hereditary elliptocytosis is often incidental.1,3
Laboratory Results for Hereditary Elliptocytosis:1,5
|
CBC: MCV: Normal to Increased MCH, MCHC: Normal |
PBS: Elliptocytes (Variable amounts) During hemolytic episodes may see: Normocytic, normochromic anemia Increased Polychromasia |
Other Tests: Osmotic Fragility: Normal Thermal Stability: Decreased PCR Hyperbilirubinemia LDH: Increased |
Hereditary Pyropoikilocytosis (HPP)
A rare variant of hereditary elliptocytosis that presents with severe hemolytic anemia.4,5
Inheritance:2,4
Autosomal recessive
Mutation:2,4
Defects in spectrin that results in red blood cell fragmentation.
Laboratory Findings for HPP:2,4,5
|
CBC: RBC: Decreased Hb: Decreased MCV: Always decreased MCHC: Increased |
PBS: Microspherocytes Schistocytes Elliptocytes |
Other Tests: Osmotic Fragility: Increased Thermal Sensitivity: Increased Eosin -5’-maleimide Binding Test: Decreased fluorescence |
Southeast Asian Ovalocytosis (SAO)
A variant of hereditary elliptocytosis that and clinical symptoms are mainly asymptomatic. Ovalocytes are large and may show one or more transverse bars in the cytoplasm of the cell. These ovalycotes are much more rigid than normal red blood cells.5 Patients are usually asymptomatic.2
Inheritance:2-4
Autosomal dominant
Mutation:2,3
Mutation in the Band 3 protein.
Laboratory Findings for SAO:5
PBS: Elliptocytes (May show one or more transverse bars)
References:
1. Gallagher PG. Abnormalities of the erythrocyte membrane. Pediatr Clin North Am [Internet]. 2013 Dec 15 [cited 2018 Jun 26];60(6):1349–62. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4155395/
2. Keohane EM. Intrinsic defects leading to increased erythrocyte destruction. In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 367–93.
3. Da Costa L, Galimand J, Fenneteau O, Mohandas N. Hereditary spherocytosis, elliptocytosis, and other red cell membrane disorders. Blood Rev [Internet]. 2013[cited 2018 Jul 24];27(4):167–78. Available from: http://www.sciencedirect.com/science/article/pii/S0268960X13000192
4. Andolfo I, Russo R, Gambale A, Iolascon A. New insights on hereditary erythrocyte membrane defects. Haematologica [Internet]. 2016 Nov 22 [cited 2018 Jun 26];101(11):1284–94. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5394881/
5. Coetzer T, Zail S. Hereditary defects of the red cell membrane. 5th ed. Philadelphia: F.A. Davis Company; 2009. p. 176–95).
