Genetics and Medicine Mutations in Globin Genes

All types of mutations have been demonstrated
in the globin genes. The most frequent are point
mutations in a single codon. The functional consequences
vary, depending on the electrical
charge and size of the substituted amino acid
and its position in the polypeptide. If one of the
hydrophilic amino acids at the surface is replaced
by a hydrophobic amino acid (e.g., valine
for glutamic acid in the sickle cell mutation),
profound physicochemical changes will result.
Mutations may decrease the elasticity of the
molecule, alter its oxygen affinity, or cause instability.