Hemoglobin is the protein that red blood cells use to bind and carry oxygen. Some genetic disorders cause problems with hemoglobin. They can affect either how much hemoglobin is made, or how the hemoglobin functions. Sickle cell and beta thalassemia are two examples of genetic disorders that affect hemoglobin.
Sickle Cell
According to the Mayo Clinic, sickle cell is a disorder in which the patient has a genetic disorder that alters the shape of hemoglobin. This causes the patients blood cells to not be soft and round and instead form a more rigid "sickle" shape. This condition causes anemia, poor blood flow, potential liver and kidney damage, and an enlarged spleen.
Beta Thalassemia
As the Genetics Home Reference explains, beta thalassemia is another genetic disorder that involves hemoglobin. Patients with beta thalassemia produce less hemoglobin than normal. This results in anemia, although the severity of the disease depends on the exact nature of the mutation; some forms of beta thalassemia cause more severe defects than others.
Combined Disorders
Sickle cell and beta thalassemia are caused by different genes. As a result, it is possible for a patient to have both diseases. This is caused by a patient getting the sickle cell gene from one parent and the beta thalassemia gene from the other parent. This can happen even if neither parent has beta thalassemia or sickle cell, because both parents could be carriers for these disorders. If the parents each have one normal copy of the hemoglobin genes, they will not have the symptoms of sickle cell or beta thalassemia, even though they carry the mutated gene.
Symptoms of Combined Disease
According to the Harvard Information Center for Sickle Cell and Thalassemia Diseases, the symptoms of combined sickle cell and beta thalassemia depend in large part on the severity of the thalassemia. Patients with the milder form of beta thalassemia essentially have a milder form of sickle cell disease, whereas those with the more severe thalassemia have symptoms that are identical to sickle cell anemia.
Prevalence
Combined sickle cell/beta thalassemia disease is the most common form of sickle cell disease in people of Mediterranean descent (including people of Italian, Greek or Turkish heritage). This is because beta thalassemia is fairly common in the Mediterranean region, and some parts of these regions are inhabited by people with the sickle cell gene.
