All of the following statements about sickle cell disease are true, EXCEPT:

In sickle cell disease glutamic acid is replaced by valine at the 6th position of the beta chain. This substitution replaces a polar glutamate residue with a non polar valine residue. As a result of this replacement a sticky patch is generated on the surface of the beta chain. This hydrophobic patch provides a surface that complements another surface feature of hemoglobin present only in the deoxygenated form. As a result, HbS in the deoxy form polymerises, forming long fibrous precipitates in the rbc. RBC distos taking on a sickle shape, and is vulnerable to lysis as it penetrates the interstices of splenic sinusoids. Ref: Medical Biochemistry: Pearls of Wisdom By Duane C. Eichler, Page 44 ; Lecture Notes on Clinical Biochemistry By Alistair Fairley Smith, Page 273 ; Human Heredity: Principles and Issues By Michael R. Cummings, Page 471