HbH is characterized by?
Alpha -Thalassemia Silent carrier state 1 gene deletion -a a a a thalassemia trait 2 gene deletion -a-a HbH disease 3 gene deletion - - -a Hydrops fetalis 4 gene deletion - - - -
Deletion of three alpha chain genes
Deletion of three alpha chains and one beta chain genes
Deletion of two alpha and two beta chain genes
Deletion of four alpha chain genes
Thalassemia