When the structure of an inherited gene contains an error and the genes control the production of an important protein such as hemoglobin, the red oxygen carrying pigment in the blood, the outcome is that the hemoglobin may not be able to do its job well. An example of this is Sickle-cell Anemia.
In this inherited condition the red blood cells are easily destroyed in the body. This condition is transferred by a single gene structure of the hemoglobin. The person inherits one gene for sickle-cell anemia from each parent. Should the individual inherit only one abnormal gene from only one parent he will have the Sickle-cell trait. The carrier of sickle-cell trait leads a completely healthy life except for extreme conditions of low oxygen. The carrier has no anemia nor symptoms. About 7% of black Americans have Sicklecell trait, and one out of 625 have the disease.
These abnormal red blood cells take on an abnormal chemical composition which leads to the decreased ability of the red blood cells to carry oxygen. This sickling shape causes clumps and clots and will block blood vessels.
The symptoms of Sickle-cell anemia are: general weakness, headaches, nausea, vomiting, fever, jaundice, and pain in muscles and joints. The blockage of the blood vessels can cause crisis which leads to the lost of function and causes pain. The crisis may involve the chest, brain, back, abdomen, and extremities.
There is no cure for Sickle-cell Anemia or the painful crisis. The treatment includes administration of fluids and pain relieving medication including narcotics.
In order to cure an inherited disease means correcting the error in a gene or replacing the abnormal protein completely.
SICKLE-CELL ANEMIA PEDIGREE
(figure available in print form)