ABSTRACT
Proteins are molecules built from amino acids, and the sequence of amino acids is determined by the sequence of nucleotides in the genome. This chapter considers how amino acid sequences are related to inherited disorders and discusses the disorder sickle cell anemia. It is caused by a mutation that gives rise to a replacement of the amino acid glutamic acid to valine in the protein hemoglobin. Sickle cell anemia is historically significant as it was the first disease to be characterized where a genetic change is associated with a well-defined change in a protein molecule. Significant advances in understanding sickle cell anemia were made by the end of the 1940s—both with respect to genetic inheritance and as to the molecular basis of the disease. Sickle cell anemia affects many hundreds of thousands around the world. The peptide in sickle cell hemoglobin was more positively charged than that of normal hemoglobin.
