Description
Hemoglobin S (Hb S) differs from the normal Hemoglobin A (Hb A) by a single amino acid mutation at position 6 of the beta
chain; wherein glutamic acid is replaced by valine. During low oxygen conditions, the red blood cell morphology may range
from mild elongation to irreversible elongated tactoid. This elongated filamentous tactoid formation results in the typical ‘sickle’
appearance of the red blood cell.
Individual with sickle cell anemia (homozygous S/S) may have early mortality with vascular occlusions of multiple organ
systems, severe hemolytic anemia and hypoxia. Individual with sickle cell trait (heterozygous A/S) are usually asymptomatic.
However, under certain conditions of reduced oxygen tension such as hypoxia during anesthesia, flight in poorly pressurized
airplanes, sever pneumonia; they can experience a sickle cell crisis.
