Blog 116: Hereditary Spherocytosis

Blog 116: Hereditary Spherocytosis

Hereditary Spherocytosis is an autosomal dominant red cell membrane defect leading to mild moderate hemolytic anemia.

For better understanding of the normal red cell membrane structure watch following video:

The RBC membrane is comprised of lipid bilayer with embedded glycolipids and various proteins in it. Also there is presence of cytoskeleton in RBCs, which helps to maintain the biconcave shape of RBCs. This biconcave structure of RBCs enable them to accommodate more amount of water when they are in a hypotonic environment. This is because it has high  surface to volume ratio.Also the lipid bilayer and cytoskeleton provide extreme flexibility and deformability to the RBCs and helps to pass through narrow vessels.

 In the narrow splenic cords the young (Flexible) RBCs can easily pass through, but the older (Less flexibility and less deformable) RBCs are trapped and destroyed by macrophages. Spherocytes has defective membranes and that defect makes them fragile and less deformable. So they are easily trapped and destroyed in spleen.

Common protein defects causing Hereditary Spherocytosis are:

Ankyrin,Band3,proteid4.1,spectrum.

Clinical features:

-Mild to moderate anaemia

- Recurrent jaundice

- Spleenomegaly

- Gall stones

Osmotic fragility test:

OFT is a screening test to detect presence of spherocytes in the blood.Here the RBCs are subjected to osmotic stress and there is rapid lysis of spherocytes.

Treatment:

- Seldom require blood transfusion.

- In severe cases spleenectomy may be performed.

For more information watch the following video: