Thalassaemia: Understanding The Basics

You may have heard of the inherited medical condition ‘thalassaemia’, especially if you are planning for a family, but may not know much about it. What are the different types of thalassaemia, and how is this condition treated? Should you be worried about thalassaemia if you are planning to start a family? Read on more below to find out about this blood disorder which could potentially be fatal.

Understanding Thalassaemia 

Thalassaemia is an inherited blood disorder (i.e. medical condition passed down from parents to children), which results from abnormal production of the components of haemoglobin. Haemoglobin is a protein molecule in our red blood cells that is responsible for transporting oxygen to all parts of our body. Thalassaemia is fairly common in Southeast Asia: about 4% of the population in Singapore are actually carriers of this disease. 

Adult haemoglobin is made up of protein chains called globin chains. There are 2 types of globin chains found in haemoglobin: alpha- (α-) and beta- (β-) globin chains. A normal, single haemoglobin molecule consists of 2 alpha- and 2 beta-globin chains.

Missing or abnormal genes that code for these globin chains will result in abnormal haemoglobin structure. This lowers the number of healthy red blood cells in the body available to transport oxygen.

There are 2 broad categories of thalassaemia, namely alpha thalassaemia and beta thalassaemia. This is dependent on which type of globin chain is abnormal or missing.

Alpha (α) Thalassaemia 

Alpha thalassaemia occurs when there is abnormality in the one or more of the four genes coding for the alpha-globin chains of the haemoglobin molecule. 

Mutations in the alpha-globin genes will lead to an unstable haemoglobin molecule. This will slow down the production of mature and healthy red blood cells in the body. As a result, the red blood cells will tend to be paler and smaller in size. These red blood cells’ ability to transport oxygen throughout your body will also be affected.

To treat alpha thalassaemia, you may require regular blood transfusions and folic acid supplements. Folic acid supplements may either be taken orally or via injections. Folic acid helps support the production of healthy red blood cells. 

If you require regular blood transfusions, you are at risk of iron overload. You may be required to undergo chelation therapy, whereby you will either take medication by mouth or via injection which helps bind to the excess iron and remove them.

Other treatment options for you may include bone marrow transplantation.

Beta (β) Thalassaemia 

Beta thalassaemia occurs when there is abnormality in the genes coding for the beta-globin chains of the haemoglobin molecule. The severity of this condition depends on whether both genes are affected and how badly the genes are affected. The lack of beta-globin chains will lead to lower amounts of mature red blood cells available in our bodies to transport oxygen. This will lead you to experience anaemia and other health issues.

Beta-thalassaemia can be split into three groups:

1. Beta thalassaemia minor (trait)

• Only one of the genes coding for the beta-globin chains is affected. 
• You would be generally asymptomatic and may often be undiagnosed. 
• A full blood test is done to detect abnormalities in the red blood cells. Tests include haemoglobin electrophoresis. 
• There is no treatment or follow up required. 

2. Beta thalassaemia intermedia

• Both genes coding for the beta-globin chains are affected.
• You would generally experience moderate to severe symptoms.
• Treatment typically includes blood transfusions every 4-6 weeks, as well as iron chelation therapy to remove excess iron from the body.

3. Beta thalassaemia major (also known as Cooley’s anaemia)

• This is the most severe form of thalassaemia and is often life-threatening.
• There is a complete lack of beta-globin chains.
• You will require to undergo regular and lifelong blood transfusions for survival.
• You will also require iron chelation therapy to prevent iron build up in your organs due to your regular blood transfusions.

Symptoms for beta thalassaemia usually start presenting in the first 2 years of life. Symptoms vary between different beta thalassaemia patients. Some of the more common symptoms include:

• Fatigue
• Pale skin
• Jaundice
• Enlargement of the liver and spleen
• Slowed growth
• Swelling of the abdomen area
• Dark urine

Should you go for screening?

Thalassaemia is a major public health issue that should not be ignored. You are strongly recommended to go for screening if you are planning to start a family, especially if you have a family history of this condition.

In Singapore, screening services are readily available in the healthcare institutions such as the polyclinics, and the hospitals. If you are detected to be carriers, you will be referred to the National Thalassaemia Registry (NTR) where professional genetic counselling will be provided.

The screening process is simple. It involves only a blood test for detailed analysis of red blood cells and haemoglobin content.

If you are a woman who is currently pregnant, you can go for prenatal screening through your gynaecologists. He/she will obtain the placenta cells at 10-12th week of pregnancy (also known as Chorionic Villus Sampling) or by Fetal Blood Sampling in the second trimester. 

Article is written in conjunction with International Thalassaemia Day 2021.