Thalassemia Trait Screening: a Real Need in the Community

What Is Thalassemia?

Thalassemia is a genetic disorder where there is abnormal hemoglobin production. This inherited disability of hemoglobin production, with a partial or complete failure to synthesize a specific type of globin chain, leads to a condition known as hemolytic anemia, in which RBC breakdown occurs. Mild jaundice can also occur.

What Are the Types of Thalassemia?

There are two types of thalassemia:

1. Thalassemia can be,

1. Alpha thalassemia.

2. Beta-thalassemia.

1. Thalassemia can be,

1. Thalassemia minor.

2. Thalassemia major.

1. Alpha and Beta-Thalassemia:

Alpha Thalassemia - In alpha thalassemia, deletion of one or both genes on the short arm of chromosome 16 may occur, with the production of some or no alpha globin chains. This reduced or absent alpha chain synthesis is common in Southeast Asia.

Since there will be a pair of alpha chain genes, the clinical manifestation depends on the number of genes deleted. Accordingly, alpha thalassemia can be classified into four types:

1. One alpha gene deletion, there is no clinical effect.

2. Two alpha gene deletion, there may be mild hypochromic anemia (clinically - microcytic hypochromic blood picture but no anemia).

3. Three alpha gene deletion, the patient has hemoglobin H disease or HbH disease (clinically - hemolytic anemia). Haemoglobin H is a beta-chain tetramer that is formed from the excess of beta chains, which is functionally useless so that patients rely on their low levels of HbA for oxygen transport. Treatment of hemoglobin H disease is folic acid supplementation, transfusion if required, and avoidance of iron therapy.

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4. Four alpha gene deletion, the baby is stillborn, that is, hydrops fetalis (clinically - fatal in utero).

Beta Thalassemia - In beta-thalassemia, there is defective production of mutations causing no or reduced beta chain production. The failure to synthesize beta chains (beta-thalassemia) is the most common type of thalassemia, which is most prevalent in the Mediterranean areas.

Depending upon the extent of reduction in beta chain synthesis, they are classified as,

1. Heterozygous form (beta thalassemia minor).

2. Homozygous form (beta thalassemia major).

3. Beta thalassemia intermedia.

a) Heterozygous Form (Beta-Thalassemia Minor): Heterozygotes have thalassemia minor, a condition in which there is usually mild anemia and little or no clinical disability, which may be detected only when iron therapy for mild microcytic anemia fails. It is a mild asymptomatic condition in which there is moderate suppression of beta chain synthesis. The diagnostic features include,

• Mild anemia.

• Microcytic hypochromic erythrocytes (not iron-deficient).

• Some target cells.

• Punctate basophilia.

• Increase in hemoglobin A2 fraction.

b) Homozygous Form (Beta-Thalassemia Major): Homozygotes have thalassemia major, and it is the most severe form of congenital hemolytic anemia and requires blood transfusions.

It is a condition where they are unable to synthesize hemoglobin A and produce very little hemoglobin, and after the first 4 to 6 months of life, they develop profound hypochromic anemia. They are further divided into two types,

• Beta degree thalassemia major characterized by the complete absence of beta chain synthesis.

• Beta plus thalassemia major is having incomplete suppression of beta chain synthesis.

The diagnostic features include,

• Profound hypochromic anemia.

• Severe red cell dysplasia.

• Erythroblastosis.

• Absence or reduction of hemoglobin A.

• Increase in levels of hemoglobin F.

• Evidence that both parents have thalassemia minor.

c) Beta-Thalassemia Intermedia: These are beta-thalassemia of an intermediate degree of severity that does not require regular blood transfusions.

2. Thalassemia Major and Minor:

Thalassemia Minor - It is where the patient inherits the gene from either parent and becomes a carrier but does not have symptoms.

Thalassemia Major - It is where the patient inherits a copy from both parents and has symptoms of severe anemia soon after birth. Here, there are several subtypes.

Thalassemia minor patients do not require a blood transfusion. They can normally live, whereas the thalassemia major patients need frequent blood transfusions, almost every 20 to 30 days. So, the detection of thalassemia minor might happen retrospectively only when a thalassemia major child is born.

What Are the Symptoms of Thalassemia?

There are several different types of thalassemia, and the signs and symptoms depend on the type and severity of the condition. Some babies start to show symptoms at the time of birth, and some start to show up after two years of age. But people affected with only one hemoglobin do not show symptoms. The common symptoms of thalassemia are,

• Fatigue.

• Pale or yellowish skin.

• Abdominal swelling.

• Facial bone deformities.

• Slow growth.

• Weakness.

• Dark urine.

How Are People With Thalassemia Diagnosed?

In order to avoid a thalassemia major child, it is really necessary to investigate for thalassemia minor before marriage or at least before conception. There are various screening methods, but ideally, to confirm thalassemia minor, HPLC (high-performance liquid chromatography) electrophoresis is the standard gold test.

So, both partners should be investigated with HPLC electrophoresis from a blood sample. 9.2 ml of blood is needed, and it is taken in an EDTA vacuette.

CBC and peripheral smear examination also can guide and can give a clue for thalassemia minor diagnosis, but they are not confirmatory. CBC shows low MCV and high RBC, and peripheral smear shows target cells and fragmented RBC.

If thalassemia minor screening has not been done before marriage, the investigation should at least be done before conception or before planning a pregnancy.

Due to lack of awareness, if the screening has not been done before marriage or conception, in the antenatal check-up, the screening should be done for the mother in the first trimester. The child's thalassemia status can also be detected in the antenatal period by invasive procedures like amniocentesis or cordocentesis. Many international organizations are working to subsidize charges for the screening test.

A thalassemia major child requires frequent blood transfusions, and the lifespan is also shortened. This increases the financial load on the family. So, this simple article is to create awareness among all the readers to kindly investigate for thalassemia minor, ideally before marriage.

What Are the Factors That Increase the Risks and Complications of Thalassemia?

Risk factors:

• Family history of thalassemia - This disease is passed from parents to children through mutated hemoglobin genes.

• People living in Africa, America, the Mediterranean, and Southeast Asia.

Complications:

• Iron overload due to frequent blood transfusions.

• Increased risk of infections.

• Bone marrow deformities make the bone brittle, bone marrow to widen, abnormal bone structure in the face and skull, and increased chances for the bone to break.

• An enlarged spleen occurs due to the destruction of a large number of red blood cells. It can worsen anemia, and the doctor suggests surgery to remove it.

• Children's growth rate is slowed down with delayed puberty.

• It results in congestive heart failure and abnormal heart rhythms.

Conclusion:

In most cases, thalassemia cannot be prevented. In case you have thalassemia, or when you carry a thalassemia gene, talk with a genetic counselor to have children. In the early stages, assisted reproductive technology diagnosis helps in screening an embryo for genetic mutations along with in vitro fertilization. This helps the parents who have thalassemia or who are carriers of a defective hemoglobin gene have healthy babies. So, reach your doctor when you result in any of the above symptoms, risks, or complications.