At age eleven, I remember my physician indicating that I had the B thalassemia trait as a child and that I was a carrier. It did not strike me as hard as it did when I found out that a friend’s aunt had recently passed away from being overcome by B Thalassemia Major. In the years to come, I understood that the only way I could ensure that I had happy, healthy children was to undergo genetic counseling with whoever was to become my husband.
When the time came, I was overjoyed to find out that my partner was not a carrier and went on to have two amazing boys, one of whom is also a carrier of the B Thalassemia Trait. The condition that causes me mild anemia was passed down from my paternal grandmother to my father, to me, and to my youngest son. I am fortunate and very grateful for the diagnosis at age eleven. I can now ensure that my youngest son will go on to raise his very own happy, healthy children.
Thalassemia is a group of related blood disorders that cause abnormal hemoglobin production. It is a genetic disorder that is recessive; therefore, both parents must be carriers to pass on the disorder in its major form. Thalassemia is categorized into two types: major and minor. Individuals suffering from the major form tend to require frequent blood transfusions to survive (Garrison & Peterson).
Other names for Thalassemia disorders are Mediterranean Anemia, Sickle Cell Anemia, and Cooley’s anemia (named after the first doctor who diagnosed it). Thalassemia disorders are usually found in people from Mediterranean descent, South East Asia, South Asia, the Middle East, China, and the Caribbean. It appears that Thalassemia arose in the areas of the world where Malaria was an epidemic. In South Africa, many people with Malaria developed Sickle cell Anemia (Garrison & Peterson).
With increased migration of people from these countries into the United States, intermarriage increasing between people from different cultural backgrounds, and more Hispanics and Latinos affected by Thalassemia disorders.
“Thalassemia is the most common inherited single gene disorder in the world.” (www.thalassaemia.us) The Thalassemias can be broken down into two main types: Thalassemia A and Thalassemia B, each giving sub-disorders.
To understand more about the differentiation of these disorders, we must first look at hemoglobin. Hemoglobin contains proteins called heme and globin. Hemoglobin production involves two sets of genes, which are produced on different chromosomes, and in turn produce two different pairs of proteins: alpha globin and beta globin. Each will contain two alpha and two beta proteins (http://medical-dictionary.thefreedictionary.com/hemoglobin).
When hemoglobin is working properly, it binds and releases oxygen. This occurs when the two alpha proteins are connected to the two beta proteins. The gene for alpha globin is located on chromosome 16, and the gene for beta globin is located on chromosome 11 (Garrison & Peterson, www.webmd.com/atozguide/thalassemia-topic-overview, 2011).
Parents determine the genes that their children inherit; hence, “thalassemia will occur if one or more of the genes fail to produce protein” (www.nhlbl.nih.gov/health-topic/topics/Thalassemia). A faulty beta globin will result in Beta Thalassemia, and a faulty alpha protein will result in Alpha Thalassemia.
There are several types of Thalassemia A. The A types include the following: Silent Carrier State – this form is difficult to detect and generally causes no health issues (www.thalassaemia.us). Hemoglobin Constant Spring – this form gets its name from where it was found in Jamaica. Like Silent Carrier, individuals do not experience health issues (www.thalassaemia.us).
Thalassemia Trait- In Thalassemia Trait, there is an increased lack of alpha proteins. It is often confused with iron deficiency anemia. Individuals have mild anemia because of smaller red blood cells (www.thalassaemia.us). Hemoglobin H Disease- Due to the lack of alpha proteins, severe anemia is reported as well as health conditions including enlarged spleen, bone malformations, and fatigue. In this disorder, hemoglobin H destroys remaining red blood cells that are created by beta globin (www.thalassaemia.us).
Hemoglobin H Constant Spring- In order for a person to have this disorder, one parent must pass the gene, and the other parent must pass the trait. These patients experience severe anemia and are more prone to enlarged spleen and frequent viral infections (www.thalassaemia.us).
The most devastating form of all Thalassemia A disorders is Hydrops Fetalis or Alpha Thalassemia Major. Babies born with this disorder die shortly after birth. Persons with Thalassemia Major have no alpha genes, resulting in gamma hematohistones producing abnormal hemoglobin called Hemoglobin Bart. If Thalassemia A is detected in utero, a technique that allows in utero blood transfusions to be performed may save the life of the unborn baby. This is a rare occurrence but has been done. (World Wide Web, thalassaemia.us)
A variation of Hemoglobin Constant Spring is called Homozygous Constant Spring. Two parents pass the gene to this child. This condition is similar to Hemoglobin H disease but less severe than Hemoglobin H Constant Spring. (World Wide Web, thalassaemia.us)
In Beta Thalassemia, if one beta hematohiston is defective, the disorder will result in Beta Thalassemia Minor. If both genes are faulty, resulting in no production of beta hematohiston, the person will have Beta Thalassemia Major. (Garrison & Peterson, ncbi.nin.gov/pubmedhealth/PMH0001613)
There are times when the clinical symptoms of thalassaemia are not so severe, resulting in a condition known as Thalassemia Intermedia. E-Beta Thalassemia is caused by one beta hematohiston mutation and hemoglobin E, causing a structural change in the hematohiston chain. This combination will cause an intermediate form of hemolytic anemia. It is more common in Asians, Cambodians, Laos, and the people of Thailand. (Garrison & Peterson, ncbi.nin.gov/pubmedhealth/PMH0001613)
In some forms of thalassemia, individuals may experience “concurrent anemia” and “iron overload.” This is caused by red blood cells that have been destroyed prematurely. When excess iron is released from destroyed red blood cells, it accumulates in the tissue of the organs such as the liver, joints, pancreas, heart, and the pituitary gland. Frequent blood transfusions can also cause iron overload. Prior to 1970, iron overload was the main reason most children with major thalassaemia died in their late teens to early twenties. (Garrison & Peterson, ncbi.nin.gov/pubmedhealth/PMH0001613)
An article from the Hematology Journal stated that “the Italian Society of Hematology is taking new measures to manage iron overload in thalassaemia major patients. ‘Superconducting quantum interference devices, magnetic resonance imaging, and oral iron chelators (deferipone and deferasirox) are all being used. Guidelines are being set for these practices.” (World Wide Web, hematology.com, 2008)
Diagnosing thalassemia can be done through various methods. Red blood cell indices are helpful in finding whether a patient has beta-thalassemia. A hemoglobin electrophoresis with a determination of elevated Hgb A2 and F is noted. Both will be increased in beta-thalassemia trait without iron deficiency and will be normal or decreased in alpha-thalassemia. It will be isolated in iron deficiency anemia. Iron deficiency can be ruled out by utilizing free red blood cell protoporphyrin beta-globulin impregnation. Ferritin saturation is a screening trial in kids who have hypochromic microcytic anemia. (McPhee & Papadakis)
The Mentzer Index also helps separate between thalassemia and iron deficiency. This index divides the red blood cell count and puts them into a mean. The mean is called the Mean Corpuscular Volume or MCV. If the results are less than 13, thalassemia is more likely. If the result is higher than 13, iron deficiency is more likely. When an MCV indicates numbers greater than 80, the person does not carry the trait. Numbers less than 80 will indicate that the patient is not iron deficient, but may be a trait bearer. Thalassemia intermedia diagnosis is made after a period of clinical observation. (McPhee & Papadakis)
In order for thalassemia major patients to survive, they need blood transfusions. Those who are chronically transfused need aggressive monitoring to maintain their well-being. Because blood transfusions can lead to iron overload, patients will need to be tested. Ferritin testing is effective for monitoring iron overload. There are several factors that can impact test results. Some of these factors are inflammation, infection of the liver, breakdown of red blood cells, errors in sample handling, vitamin C deficiency, and excessive alcohol intake the night before testing. (McPhee & Papadakis)
A liver biopsy is the second step in testing. However, it is not the choice of testing for thalassemia patients. The test is invasive and there is a longer recovery time. Direct sampling from the body tissue helps measure the iron overload. The third and most accurate form of testing is MRI-based technology with R2 and T2 techniques. Measuring iron overload in the liver is done with the R2 technique and measuring cardiac damage from iron overload is done with the T2 technique. (McPhee & Papadakis)
Treatment for hemoglobin H disease is folate supplementation and avoidance of medicative iron and oxidative drugs like sulfa drugs. (www.thalassaemia.com) In the United States, there are two approved iron chelators used for removing iron from iron overload. Desferal (deferoxamine) is administered by subcutaneous injection. The procedure takes eight to twelve hours and is done five to seven nights a week. In 2005, an oral chelator, Exjade (deferasirox) was used. It is taken one time per day. (McPhee & Papadakis)
Symptoms of Thalassemia vary depending on the type of the disorder. In mild cases, individuals appear clinically normal, have a normal life expectancy, and exhibit normal performance status. Some may have mild microcytic anemia. With the more severe type B, for example, children appear normal at birth, but after six months, they develop severe anemia due to the switch from F to A hemoglobin. These children experience growth failure, bone malformations, and hepatosplenomegaly (enlargement of the liver and spleen) and jaundice. They survive into childhood, but with skeletal malformations and hepatosplenomegaly. (McPhee & Papadalis)
In Italy, experimental bone marrow grafts are being researched and have proven effective in reversing cirrhosis of the liver in six Thalassemia patients. Precise bone marrow donors are required for this process. Like all surgeries, there is a risk of infection or even death. Researchers are investigating gene therapy as a possible treatment approach. Gene therapy and fetal hemoglobin are techniques used in which the scientist inserts a normal fetal gene into the stem cell of the unborn child with Thalassemia. It is believed that one day, it will be possible to cure an unborn child. (Medical News Today, 2010)
The best way to prevent this disorder is by educating others about it, performing parental diagnosis before pregnancy, and genetic counseling. Knowing one’s own body by obtaining regular medical check-ups and laboratory tests in addition to inquiring about family members’ medical history is the best prevention method for passing on a potential genetic disorder.
Bibliography:
- (n.d.). Retrieved from www.thalassaemia.com. (2008).
- Hematology Journal. doi:10.3324/haematol.12413. (2008, April). Retrieved from www.hemotolgy.com. (2010, July 15).
- Retrieved from Medical News Today, www.medicalnewstoday.com.
- Retrieved from WebMD, www.webmd.com/atozguide/thalassemia-topic-overview. (2011, July).
- Garrison, C. D., & Peterson, C. M. (n.d.). The Iron Disorders Guide to Anemia. http://medical-dictionary.thefreedictionary.com/hemoglobin.
- (n.d.). McPhee, S. A., & Papadalis, M. A. (n.d.). 2011 Current Medical Diagnosis and Treatment. www.ncbi.nin.gov/pubmedhealth/PMH0001613.
- (n.d.). www.nhlbl.nationalinstitutesofhealth.gov/health-topic/topics/Thalassemia.
- (n.d.). www.thalassaemia.us.
