SICKLE CELL DISEASE

Sickle cell disease is a genetically determined disorder of the red blood cell in which the protein structure of the ?subunit of the hemoglobin molecule is abnormal. A single base pair substitution in codon 6 causes the amino acid valine to be switched for glutamate. Under conditions of low oxygen tension, the abnormal hemoglobin precipitates. The erythrocyte deforms, assuming a sickle shape. The sickled cells do not circulate well; the hemoglobin polymerizes(if deoxygenated), leading to anemia, tissue oxygen starvation and infarction. Clinically, the patient suffers painful crises.