Mediterranean anemia is an older name for beta-thalassemia, an inherited blood disorder in which the body produces less hemoglobin than normal. The name comes from the condition’s high prevalence in Mediterranean countries like Italy, Greece, and Cyprus. It ranges from a mild form that causes no noticeable symptoms to a severe, life-threatening anemia that requires regular blood transfusions starting in infancy.
How Mediterranean Anemia Affects the Blood
Hemoglobin, the protein inside red blood cells that carries oxygen, is built from two types of protein chains: alpha and beta. In beta-thalassemia, mutations in the HBB gene reduce or completely stop the production of beta chains. Without enough beta chains, the excess alpha chains become unstable and damage developing red blood cells from the inside. The result is red blood cells that are smaller than normal, break apart easily, and don’t carry oxygen efficiently.
This combination of fragile red blood cells and poor oxygen delivery is what produces anemia. In mild cases, the body compensates reasonably well. In severe cases, the bone marrow works overtime trying to produce enough red blood cells, which can eventually cause bones to thin and reshape, particularly in the face and skull.
Three Levels of Severity
Thalassemia Minor (Trait)
People with thalassemia minor carry one altered copy of the HBB gene and one normal copy. Most have mild anemia or no symptoms at all, and many don’t realize they carry the trait until a routine blood test flags slightly small red blood cells. No treatment is needed, but knowing your carrier status matters for family planning.
Thalassemia Intermedia
This moderate form appears in early childhood or sometimes later. It causes mild to moderate anemia, slower growth, bone changes, and a higher risk of abnormal blood clots. Most people with thalassemia intermedia do not need regular transfusions, though they may need them occasionally during illness or pregnancy.
Thalassemia Major (Cooley’s Anemia)
The most severe form shows up within the first two years of life. Children develop life-threatening anemia, fail to gain weight or grow at a normal rate, and often develop jaundice. The spleen, liver, and heart can enlarge, and bones may become misshapen as the marrow expands in a desperate attempt to produce more red blood cells. Puberty is often delayed. Without treatment, thalassemia major is fatal in early childhood. With modern care, including regular blood transfusions, most people survive well into adulthood.
Who Is Most Likely to Have It
Beta-thalassemia is most common in populations from the Mediterranean region, the Middle East (Iran, Iraq, Saudi Arabia), and parts of South and Southeast Asia (India, Pakistan, Bangladesh). Carrier rates in these regions range from 1% to 20%, and in certain Middle Eastern and Indian populations, carrier rates can reach as high as 40%.
The trait likely persisted because carrying one copy of the mutated gene offers some protection against malaria, similar to the sickle cell trait. This is why thalassemia tracks closely with regions where malaria was historically endemic.
How It’s Inherited
Beta-thalassemia follows an autosomal recessive pattern. You need to inherit an altered HBB gene from both parents to develop the moderate or severe forms. If both parents carry thalassemia minor, each pregnancy carries a 25% chance of producing a child with thalassemia major, a 50% chance of producing another carrier, and a 25% chance of producing a child with two normal copies. Genetic testing and carrier screening are particularly valuable for couples from high-prevalence populations who are planning to have children.
How It’s Diagnosed
A standard complete blood count often provides the first clue: small red blood cells with low hemoglobin. But small red blood cells also show up in iron deficiency anemia, which is far more common. The key test that separates the two is hemoglobin electrophoresis, which measures the different types of hemoglobin in the blood. In beta-thalassemia carriers, a protein fraction called Hemoglobin A2 is elevated above 3.5%, with most carriers showing levels at or above 4.0%. People with thalassemia major typically show very high levels of fetal hemoglobin (Hemoglobin F), which the body produces as a workaround when it can’t make normal adult hemoglobin.
One common mistake is treating small red blood cells with iron supplements before checking whether thalassemia is the cause. If you already have thalassemia, unnecessary iron supplementation can be harmful because the condition already predisposes the body to absorbing and storing too much iron.
Iron Overload: The Major Complication
Iron overload is the most serious long-term threat for people with thalassemia major. Each blood transfusion delivers a large dose of iron, and the body has no natural mechanism for excreting excess iron. Over time, iron accumulates in the liver, heart, and hormone-producing glands. Cardiac iron overload is particularly dangerous because it can cause heart muscle disease, heart failure, and irregular heart rhythms. These cardiac complications are a leading cause of death in thalassemia patients.
Iron also damages the endocrine system, which can lead to diabetes, thyroid problems, and delayed or absent puberty. Liver damage from iron overload can progress to scarring and cirrhosis. Managing iron levels is just as critical as the transfusions themselves.
To prevent iron overload, people who receive regular transfusions take iron chelation medications. These drugs bind to excess iron in the body so it can be excreted through urine or stool. Chelation therapy typically becomes a lifelong commitment for anyone on a regular transfusion schedule, and iron levels are monitored through blood tests and periodic MRI scans of the heart and liver.
Living With Thalassemia Major
People with transfusion-dependent thalassemia typically receive blood transfusions every two to four weeks to keep their hemoglobin at functional levels. Each session takes several hours, and the schedule is a significant part of daily life. Between transfusions, energy levels can dip as hemoglobin gradually falls. Many people learn to plan demanding activities for the days immediately following a transfusion, when they feel their best.
Bone health requires attention because the disease itself weakens bones, and hormone disruptions from iron overload can accelerate bone loss. Spleen enlargement is common, and some people eventually need their spleen removed, which improves anemia but increases vulnerability to certain infections.
Gene Therapy: A Potential Cure
For decades, the only potential cure for thalassemia major was a bone marrow transplant from a matched donor, which carries significant risks and isn’t available to most patients. That changed with the arrival of gene therapies.
Two gene therapies are now approved for transfusion-dependent beta-thalassemia. The first, approved by the FDA in 2022, works by inserting a functional copy of the beta-globin gene into a patient’s own stem cells. In clinical trials, roughly 89% to 91% of patients achieved transfusion independence, meaning they no longer needed regular blood transfusions at all. A second gene therapy, approved in January 2024, uses CRISPR gene-editing technology to boost fetal hemoglobin production. In its clinical trial, 91% of patients achieved transfusion independence, with red cell transfusions stopping an average of about 35 days after the single infusion.
Both therapies involve collecting the patient’s stem cells, modifying them in a lab, and infusing them back after chemotherapy clears space in the bone marrow. The process requires several months of medical care, including weeks in the hospital. These treatments are extremely expensive and currently available only at specialized centers, but they represent the first realistic path to a cure for many people who previously faced a lifetime of transfusions.