The question given was: “Which of the following diseases is not hereditary? ” The choices are: sickle-cell anemia, cystic fibrosis, diabetes, arthritis or all of the above choices. To answer this question, it is necessary to define first what a hereditary disease is. A hereditary disease is a specific case of genetic disorder, where defective genes are often inherited from the parents. This can often happen unexpectedly when two healthy carriers of a defective recessive gene reproduce, but can also happen when the defective gene is dominant.
Sickle-cell anemia is a disorder that occurs when a person inherits two abnormal genes , one from each parent. It’s a condition where the red blood cells were abnormally shaped, that instead of being round and flexible, they are more rigid and curved in the shape similar to a crescent moon. This is caused by a single amino-acid substitution in the beta chains of hemoglobin. Cystic fibrosis is a hereditary disorder caused by a defective gene which codes for CFTR (cystic fibrosis transmembrane conductance regulator), a membrane protein that pumps Cl- out of cells.
If the Cl- pump is defective, Cl- ions remain in cells, which then take up water from the surrounding mucus by osmosis. The mucus thickens and accumulates in various organs. Diabetes is a disease in which the body loses its ability to regulate the amount of a certain sugar (glucose) in the blood. Glucose serves as food for the cells of your body. Without the ability to maintain a constant supply of glucose, organs, (including the brain) become starved. The main controller of glucose concentration in the blood is the hormone insulin.
Diabetics have to externally monitor the amount of glucose in their blood, and regulate it with insulin injections. Studies of identical twins have revealed that diabetes is, in part, hereditary. If one identical twin becomes diabetic, the other twin is at increased risk of developing the disease. However in some sets of identical twins, one twin will develop diabetes and the other will not. Arthritis, in general terms, is inflammation and swelling of the cartilage and lining of the joints, generally accompanied by an increase in the fluid in the joints.
Arthritis has multiple causes; just as a sore throat may have its origin in a variety of diseases, so joint inflammation and arthritis are associated with many different illnesses. Besides heredity, arthritic symptoms may have their source in a number of phenomena: they can be traumatic, having their origins in injuries, notably in athletes and industrial workers, especially if the injuries have been ignored (which injuries of the feet tend to be). Thus all the choices are affected by heredity in one way or another.
REFERENCE
Garrett, R and C. Grisham (2005). Biochemistry. United States: Brooks/Cole.