EL4: Southeast Asian ovalocytosis is associated with the Band 3 protein.Similarly to the spectrin mutations, band 4.1 mutations cause a mild haemolytic anaemia in the heterozygous state, and a severe haemolytic disease in the homozygous state. Spectrin tetramers must bind to actin in order to create a proper cytoskeleton scaffold, and band 4.1 is an important protein involved in the stabilisation of the link between spectrin and actin. EL1: Less common than spectrin mutations are band 4.1 mutations.they are heterozygous for two different elliptocytosis-causing mutations) have sufficient cell membrane instability to have a clinically significant haemolytic anaemia. Individuals with a single mutation in one of the spectrin genes are usually asymptomatic, but those who are homozygotes or are compound heterozygotes (i.e. In both cases the end result is a weakness in the cytoskeleton of the cell. In contrast, it is generally true that β-spectrin mutations lead to αβ heterodimers being incapable of combining to form spectrin tetramers. Although there is much interindividual variability, it is generally true that α-spectrin mutations result in an inability of α-spectrin to interact properly with β-spectrin to form a heterodimer. These spectrin tetramers are among the basic structural subunits of the cytoskeleton of all cells in the body. ![]() These αβ heterodimers then combine to form spectrin tetramers. These two polypeptides combine with one another in vivo to form an αβ heterodimer. EL2 and E元: The most common genetic defects (present in two-thirds of all cases of hereditary elliptocytosis) are in genes for the polypeptides α-spectrin or β-spectrin.Figure 2 - A schematic diagram representing the relationships between cytoskeletal molecules as relevant to hereditary elliptocytosis. These elliptical cells are taken up by the spleen and removed from circulation when they are younger than they would normally be, meaning that the erythrocytes of people with hereditary elliptocytosis have a shorter than average life-span (a normal person's erythrocytes average 120 days or more). Normally, this deformation lasts only as long as a cell is present in a capillary, but in hereditary elliptocytosis the instability of the cytoskeleton means that erythrocytes deformed by passing through a capillary are forever rendered elliptical. As disc-shaped erythrocytes pass through capillaries, which can be 2-3 micrometres wide, they are forced to assume an elliptical shape in order to fit through. This stability is especially important in erythrocytes as they are constantly under the influence of deforming shear forces. These mutations have a common end result they destabilise the cytoskeletal scaffold of cells. Pathophysiology Common hereditary elliptocytosis Ī number of genes have been linked to common hereditary elliptocytosis (many involve the same gene as forms of Hereditary spherocytosis, or HS): Most cases are asymptomatic with abnormalities in their peripherial blood film. ![]() RBCs are elleptical in shape rather than normal biconcave shape. Although pathological in humans, elliptocytosis is normal in camelids. In its severe forms, this disorder predisposes to haemolytic anaemia. It is one of many red-cell membrane defects. ![]() Such morphologically distinctive erythrocytes are sometimes referred to as elliptocytes or ovalocytes. Hereditary elliptocytosis, also known as ovalocytosis, is an inherited blood disorder in which an abnormally large number of the person's red blood cells are elliptical rather than the typical biconcave disc shape. Peripheral blood smear showing an abundant number of elliptocytes Any duplication or distribution of the information contained herein is strictly prohibited.Medical condition Hereditary elliptocytosis No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. Links to other sites are provided for information only – they do not constitute endorsements of those other sites. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. This site complies with the HONcode standard for trustworthy health information: verify here. ![]() Learn more about A.D.A.M.'s editorial policy editorial process and privacy policy. is among the first to achieve this important distinction for online health information and services. follows rigorous standards of quality and accountability. is accredited by URAC, for Health Content Provider (URAC's accreditation program is an independent audit to verify that A.D.A.M.
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