Hereditary spherocytosis is due to deficiency -
Hereditary spherocytosis (HS)

Hereditary spherocytosis is an inherited disorder, caused by intrinsic defects in the red cell membrane that is characterized by the production of red cell that is sphere-shaped rather than a biconcave doughnut-shaped, and therefore are sequestrated in spleen and destroyed there.

A structural defect in Hereditary spherocytosis

Membrane-cytoskeleton that lies closely opposed to the internal surface of the plasma membrane, is responsible for elasticity and maintenance of RBC shape.
Membrane skeleton consists :



Spectrin →The chief protein component.


Ankyrin and band 4.2 → Binds spectrin to band 3


Band 3 → A transmembrane ion transport protein.


Band 4.1 → Binds spectrin to glycophorin A, a transmembrane protein.



Hereditary spherocytosis is caused by a variety of molecular defects in genes that code for any of the following:-
Ankyrin → Most common
Band 3 → Second most common
Spectrin CI
Band 4.2



Hereditary spherocytosis is acquired as autosomal dominant in the majority of the cases. In some cases, the autosomal recessive pattern of inheritance is seen.
Spectrin
Invertin
Cytokeratin
All of the above