![]() Sickle Cell (1 of 3) Genes Sickle cell anemia is caused by a mutation at the genes level.
 |  | ![]() Sickle Cell (2 of 3) Protein Normal hemoglobin (left) and hemoglobin in sickled red blood cells (right) look different; the mutation in the genes changes the shape of the hemoglobin molecule, allowing it to clump together.
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