_IMG_01_12-sickle_cell_mutation.jpg AligN=MiddlE A single nucleotide change (mutation) in the DNA encoding the beta globin gene (CTC -> CAC) leads to an altered mRNA codon (GAG -> GUG). The resulting change in the amino acid (glu -> val) produces a mutant beta globin, causing sickle cell _SIZ_sickle_cell_anemia.html anemia.