A single nucleotide substitution: Glu6Lys.

Mutation is on the β-chain.

Oxygenated HbC tends to crystallize, causing less deformable cells, causing mild hemolysis.

Both amino acids glutamate and lysine are on the surface.

The cells become more rigid

A more mild version of sickle-cell anemia.

This disease has an autosomal recessive pattern of inheritance.