When translated into amino acids, this mutation results in the amino acid glutamate being replaced by the amino acid valine in a critical region of the hemoglobin protein, the major oxygen-transporting component of red blood cells. The consequences of this tiny change in the protein—a difference of just ten atoms out of more than eight thousand total—are dire. The mutated hemoglobin molecules stick together and form abnormal filaments that change the shape of the red blood cells, which leads to anemia, increased risk of stroke and infection, and severe bone pain.
