All the following are true about sickle cell anemia except
Mutation in alpha chain
Symptoms ameliorated by Hbf
Venoocclusive cries is cause of morbidity
Bone pain is presenting feature
Ref Harrison 19 th ed pg 634 The sickle cell syndromes are caused by a mutation in the b-globin gene that changes the sixth amino acid from glutamic acid to valine. HbS (a2 b2 6 Glu-Val) polymerizes reversibly when deoxygenated to form a gelatinous network of fibrous polymers that stiffen the RBC membrane, increase viscosity, and cause dehydration due to potas- sium leakage and calcium influx.
Haematology