Miscellaneous Red Cell Abnormalities

Introduction In the chapter of Miscellaneous Red Cell Abnormalities, we will discuss some of the commonly seen red blood cell abnormalities. Adult human bone marrow synthesizes 4 X 1014 molecules of hemoglobin every second. Heme and globin chains (alpha and beta) in adults are manufactured in separate cell compartments—mitochondria and cytoplasm, respectively—and then combined in the cytoplasm in an amazingly accurate manner. Four major […]

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Sickle Cell Disease

Sickle cell disease (HbS) is a severe hereditary form of anemia in which a mutated form of hemoglobin distorts the red blood cells (RBC’s) into a crescent shape at low oxygen levels. Sickle cell disease (HbS) is commonest among those of African descent. In this disease, a single base mutation in the β-globin gene leads to the substitution of valine for […]

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Thalassemia Facies

What are Thalassemias? Thalassemias are inherited blood disorders in which the body makes an abnormal form of hemoglobin. Hemoglobin is the protein molecule in red blood cells that carries oxygen. These disorders result in excessive destruction of red blood cells, which leads to anemia. In thalassemias, there is an abnormality of one or more of the globin genes leading to […]

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Pyruvate Kinase Deficiency


Pyruvate kinase deficiency (PKD) is one of the most common enzymatic defects of the RBCs, it manifests clinically as hemolytic anemia that can range from mild to severe. There are many different types of enzyme-related defects of the red blood cell that can cause hemolytic anemia. PKD is the second most common cause, after glucose-6-phosphate dehydrogenase (G6PD) deficiency. PKD is inherited […]

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G6PD Deficiency

Introduction: Glucose 6 phosphate dehydrogenase (G6PD) deficiency affects approximately 400 million individuals worldwide. It is the most common human enzyme defect. The global distribution of this disorder is remarkably similar to that of malaria, lending support to the so-called malaria protection hypothesis. It is common in Africa, around the Mediterranean, and in the Orient. G6PD deficiency is an X-linked recessive disorder. The hereditary genetic […]

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Paroxysmal Nocturnal Hemoglobinuria


Introduction: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired, life-threatening disease of the blood. The disease is characterized by destruction of red blood cells by the complement system, a part of the body’s innate immune system (hemolytic anemia), blood clots (thrombosis), and impaired bone marrow function (not making enough of the three blood components). PNH is the only hemolytic anemia caused by an acquired (rather than […]

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Acanthocytes (spur cells) are spiculated red cells with a few projections of varying size and surface distribution. The formation of acanthocytes depends on the alteration of the lipid composition and fluidity of the red cell membrane. Acanthocytosis may be inherited (autosomal recessive) in association with retinitis pigmentosa, diffuse neurological deficits, and abetalipoproteinemia. In abetalipoproteinaemia, an autosomal recessive condition, vitamin E […]

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Stomatocytes (RBCs with slit-like central pallor) Stomatocytosis is a rare condition of RBCs in which a mouthlike or slitlike pattern replaces the normal central zone of pallor. These cells are associated with congenital and acquired hemolytic anemia. The symptoms result from the anemia. Stomatocytes are erythrocytes with a central slit or stoma instead of a circular area of pallor when examined […]

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Hereditary Elliptocytosis (HE), also known as ovalocytosis, is a disorder of the red cell membrane inherited usually in an autosomal dominant pattern. In this condition, the majority of cells have an elliptical shape. The osmotic fragility is normal. HE is due to defects in either the structure or quantity of the cytoskeletal proteins responsible for maintaining the biconcave morphology of RBCs. Mutations […]

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