The causes of thalassemia that need to be known

Thalassemia is a genetic disease of red blood cell disorders that makes hemoglobin in the blood unable to circulate oxygen throughout the body properly. This causes sufferers to feel the symptoms of anemia, ranging from mild to severe and dangerous. What exactly causes thalassemia? Why do people with thalassemia have problematic hemoglobin? To understand what caused this condition, see the review below.

What are the causes of thalassemia?

The main cause of thalassemia is a genetic mutation. This means that there are abnormal or problematic genes that cause a person to experience thalassemia.

There are two genes that play a role in the formation of red blood cells, namely:

• HBB (hemoglobin beta subunit)
• HBA (alpha subunit hemoglobin) 1 and 2

Both the HBB and HBA genes are responsible for providing instructions to produce proteins called alpha and beta chains. Later, the alpha and beta chains will form hemoglobin to transport oxygen in red blood cells to be distributed throughout the body.

In people with thalassemia, there is one HBB or HBA gene that is reduced or damaged. Damage or mutation in this gene can be passed down from parents with the problematic gene as well.

If one parent has a genetic mutation that causes thalassemia, the baby is born likely to have mild thalassemia or no symptoms at all (thalassemia minor). However, if both parents have mutated genes, the baby born will be at risk of developing severe thalassemia (major).

Thalassemia can be divided into 2 types, depending on the alpha or beta chains that are affected.

Causes of alpha thalassemia

One type of thalassemia is alpha thalassemia, which is when damage occurs to the HBA gene.

In healthy hemoglobin, there are 2 HBA1 genes and 2 HBA2 genes. That is, it takes 4 HBA genes to form normal hemoglobin.

Alpha thalassemia occurs because one or more of the HBA genes are mutated. Later, the severity of alpha thalassemia will depend on how many genes are damaged or mutated.

1. One mutated gene

If a person only has 1 of the 4 mutated HBA genes, it will only become carrier or carriers of mutated gene traits. In other words, this condition does not cause severe alpha thalassemia. In fact, some people with this condition don't usually feel the signs and symptoms of thalassemia.

2. Two mutated genes

If there are 2 of the 4 mutated HBA genes, signs and symptoms of alpha thalassemia are still relatively mild. In medical terms, this condition is also called alpha thalassemia trait.

3. Three mutated genes

The signs and symptoms that appear if there are 3 out of 4 mutated genes will certainly be heavier and require more intensive thalassemia treatment, such as routine blood transfusions. At this level, a person can experience severe symptoms of anemia and are at risk for other complications of thalassemia.

4. Four mutated genes

This condition is very rare and is also known as Hb Bart syndrome. In this condition, all HBA genes have mutations and cause the most severe thalassemia.

Babies born with this condition have very little chance of survival. Thus, most babies with Hb Bart syndrome die before birth, or shortly after birth.

Causes of beta thalassemia

Almost the same as alpha thalassemia, the cause of beta thalassemia is damage to the HBB gene. The difference is, the number of HBB genes is generally less than HBA.

You need 2 normal HBB genes to form healthy hemoglobin. In cases of beta thalassemia, damage can occur to one or both of the HBB genes.

If only 1 out of 2 HBB genes are damaged, the patient will develop mild or minor beta thalassemia.

However, if both HBB genes are damaged, the thalassemia will be classified as intermedia or major with a more severe severity.

Thalassemia risk factors

The main cause of thalassemia is the presence of genetic factors that are inherited from parents. However, besides that, people of certain races also have a higher risk of developing thalassemia.

It is not certain how race can be a risk factor for thalassemia. However, the incidence of thalassemia is indeed higher in people of certain racial descent.

There is also a theory which states that the distribution of thalassemia to several races occurs because it follows the thalassemia belt (thalassemia belt). That is, the spread of this disease follows the direction of early human migration in ancient times.

According to the Northern California Comprehensive Thalassemia Center website, here is a list of races with the most cases of thalassemia:

• Southeast Asia (Indonesia, Malaysia, Singapore, Vietnam, Laos, Thailand and the Philippines)
• China
• India
• Egypt
• Africa
• Middle East (Iran, Pakistan, and Saudi Arabia)
• Greece
• Italy

Thalassemia is not a disease that can be cured. However, to anticipate various possibilities, it is very important for you and your partner to do so premarital checkup or prenuptial examinations. That way, the opportunity to give birth to a child with thalassemia is expected to be minimized with better planning.