Hereditary elliptocytosis

One of the most frequent red blood cell membrane disorders with a frequency of I in 2000-5000 persons depending upon the population.

In parts of Africa the incidence approaches that of sickle cell disease because hereditary elliptocytosis red cells confer some resistance to invasion by malaria parasites.

Mutations in alpha-spectrin account for the majority of cases with the remaining cases arising from beta-spectrin mutations or protein 4.1R.

Most cases are due to missense mutations in the erythrocyte membrane skeleton protein spectrin.

Most common mutations associated are in the SPTA1 gene, which encodes a-1spectrin.

Numerous mutations in SPTA1 present in this entity and hereditary pyropoikilocytosis.

Many SPTA1 mutations cause changes in amino acids at the a-I-spectrin site that binds to bI-spectrin in the formation of spectrin tetramers.

Spectrin tetramers provide resistance to red blood cell shear stresses in the circulation.

Spectrin is a critical component of red cell membrane skeleton, a network of proteins on the cytoplasmic face of the membrane that maintains the shape and elasticity of the RBC membrane.

Spectrin exist as an anti-parallel alpha-beta-heterodimer in the red cell that associates in a head-to-head fashion to form tetramers and oligomers.

Clinically the phenotype varies from asymptomatic to severe hemolytic.

A related condition hereditary pyropoikilocytosis (HPP) is an aggravated form of hereditary elliptocytosis.

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