Many different types of mutations can occur within the body. sickle cell anemia is a disease that occurs when a mutation in a base pair of the hemoglobin beta gene causes a single replacement of the amino acid glutamic acid by the amino acid valine. as a result of this mutation, the individual’s blood cells take on a sickle shape under certain conditions and form clusters that can block blood vessels and cause organ damage. mc017-1.jpg mc017-2.jpg which type of mutation causes sickle cell anemia?