Thalassemia is the most common inherited single gene disorder in the world. It affects a significant percentage of children born in the Middle East, India, Africa, Southeast Asia, southern China and the Mediterranean.
Diagnosed in infancy or early childhood, children with thalassemia produce red blood cells with a mutation that affects hemoglobin production. Hemoglobin is the protein in red blood cells that helps them carry oxygen. There are two hemoglobin chains, either of which may be affected. A mutation in the alpha chain, more common in Southeast Asia and China, may cause stillbirth in its most severe form.
A mutation in the beta chain of hemoglobin may result in either thalassemia minor or thalassemia major:
Thalassemia minor, or thalassemia trait, occurs when just one mutated beta chain gene is inherited (only one parent carries the mutated gene). The affected child will generally have no symptoms and require no treatment, although mild to moderate anemia is not uncommon. People with thalassemia minor are carriers of the disease, with a 50% chance of passing the defect on to their own children. If both parents have thalassemia minor, there is a 25% chance that they will have a child with thalassemia major.
Thalassemia Major (Cooley’s Anemia):
Thalassemia major, also called Cooley’s Anemia, occurs as a result of inheriting mutated genes for beta chains from both parents. While the affected child appears normal at birth, they quickly become pale and fussy and may suffer from frequent infections. They often become profoundly anemic as infants and require lifelong transfusion therapy. As they grow older, the physical manifestations of thalassemia major can range from mild to devastating.
Slow growth and weakness become apparent in the second year of life. Children with moderate to severe disease have stunted growth and extended bellies caused by liver enlargement. They may also develop facial bone deformities, suffer from fatigue and experience shortness of breath.
Treatment for thalassemia major includes oral medications and blood transfusions every three to four weeks for the life of the child. Chronic transfusion therapy, however, causes iron to deposit in the liver, heart, kidneys and other organs. The iron overload will eventually damage or destroy organs and must be managed by the daily 12-hour IV administration of a drug that binds the iron and washes it out of the blood (chelation therapy). The near impossibility of complying with this enormous daily burden often results in early death.
Children born with severe forms of thalassemia now routinely live into their 20’s with regular transfusions and daily IV chelation therapy. Conservative estimates would suggest that several million children and young adults worldwide suffer from either thalassemia or sickle cell disease, the most common of the inherited red blood cell disorders.