Sickle cell and thalassaemia (red cell service)

Sickle cell disease (SCD) is a serious inherited blood disorder in which the red blood cells that carry oxygen throughout the body develop abnormally.  

The condition primarily affects individuals of African, Caribbean, Middle Eastern, Eastern Mediterranean, and Asian origin. In the UK, it is most commonly seen in people of African and Caribbean heritage. 

In healthy people, red blood cells are flexible, and disc shaped. However, in those with SCD, these cells can become rigid and crescent-shaped, or ‘sickle’ shaped, due to a mutation in haemoglobin, the iron-rich protein responsible for transporting oxygen from the lungs to the body.  

This mutation results in cells that are not only misshapen but also less able to move smoothly through blood vessels, which can cause blockages and lead to significant tissue and organ damage, as well as life-threatening complications. 

Episodes of blocked blood flow, known as sickle cell crises or vaso-occlusive crises, are hallmark complications of SCD. These crises, which can last from minutes to weeks, often involve intense pain and may result in severe conditions, such as stroke or acute chest syndrome.  

In addition, the abnormally shaped blood cells have a shorter lifespan and are not replaced as quickly, leading to anaemia, with symptoms like fatigue, breathlessness, and reduced stamina. 

Treatment for SCD is currently limited, with bone marrow transplantation being the only potential cure. However, transplantation is associated with considerable risks, and experience in treating SCD with this method is still evolving.  

Increasing numbers of bone marrow transplants are being performed as specialists develop expertise in this area. Most treatments focus on preventing serious complications before they occur, aiming to support patients’ health and wellbeing effectively. 

Beta thalassaemia is part of a group of inherited blood disorders collectively known as thalassaemia, characterised by abnormalities in haemoglobin (Hb) — the protein within red blood cells responsible for carrying oxygen throughout the body.  

Due to these genetic abnormalities, red blood cells cannot function properly, leading to anaemia, a deficiency of red blood cells. The severity of thalassaemia syndromes is determined by the number of missing or altered genes that guide haemoglobin production. 

In beta thalassaemia, there are only two beta genes, one on each copy of chromosome 11, unlike the alpha genes, which are more numerous. This disorder can vary in severity, from moderate to severe: 

• Beta thalassaemia major (transfusion-dependent thalassaemia, TDT): this is the most severe form and occurs when both beta genes are affected. People with TDT require lifelong blood transfusions, starting within the first few weeks to months of life. 

• Beta thalassaemia intermedia (non-transfusion-dependent thalassaemia, NTDT): this milder form presents with varying symptoms from person to person. While some people experience mild anaemia, others may occasionally need blood transfusions. 

Our services focus primarily on caring for patients with beta thalassaemia major (TDT), the most common and severe form of this condition in the UK. 

Global prevalence of thalassaemia

Thalassaemia affects populations worldwide, with a high prevalence in Southeast Asia, and it is also common among people of Mediterranean, North African, Middle Eastern, Indian, and Asian origin. 

For additional information on beta thalassaemia or to explore the support and treatment options we offer, please contact our team. 

Alpha thalassaemia is an inherited blood disorder caused by abnormalities in the alpha chains of haemoglobin, which are produced by four genes, two on each copy of chromosome 16.  

The severity of alpha thalassaemia depends on how many of these genes are affected: 

• One gene altered: minimal or no effect. Individuals with one altered gene typically experience no symptoms. 

• Two genes altered: this condition, known as the alpha thalassaemia trait or carrier state, may cause mild anaemia. Carriers can pass this trait to their children but usually experience no serious health issues themselves. 

• Three genes altered (haemoglobin H disease): people with three affected genes develop haemoglobin H (HbH) disease, leading to chronic anaemia. Although they may require occasional blood transfusions, not all patients need them regularly. 

• Four genes altered (alpha thalassaemia major): this most severe form, occurs when all four genes are altered. Infants with this condition cannot produce normal haemoglobin, leading to a high risk of stillbirth or death shortly after birth. In rare cases, unborn babies may be treated with in-utero blood transfusions, but this approach is complex and has a low success rate. 

When two carriers of the alpha thalassaemia zero trait (two altered genes on the same chromosome) have a child, there is a 25% chance the child will inherit alpha thalassaemia major. 

It is common in people with origins from  

• China  

• Hong Kong  

• Thailand  

• Vietnam  

• Philippines 

• Cyprus  

• Greece 

• Southern Italy  

For more information on managing alpha thalassaemia or to learn about the support services we provide, please contact our team. 

Haemoglobin is an iron-containing protein made up of alpha, beta, gamma, and delta globin chains. Changes to the structure of these chains can lead to haemoglobin abnormalities.  

Certain unusual haemoglobins may interact with genes associated with sickle cell disease or beta thalassaemia, which can sometimes lead to health issues. However, children who inherit two unusual haemoglobin traits often remain generally healthy without significant health problems. 

Haemoglobinopathies occur when genetic variants in the genes responsible for producing globin chains lead to abnormal haemoglobin production. These genetic changes can result in either reduced production of one or more globin chains or the creation of structurally altered globin chains.  

Globally, approximately 7% of people carry at least one haemoglobin variant (are carriers), though this rate can vary significantly based on ethnicity. 

These variants can affect haemoglobin in several ways, including altering its structure, changing how it behaves, affecting its production rate, or impacting its stability.  

Red blood cells with abnormal haemoglobin may have altered size, shape, and reduced functionality. When these cells carry oxygen less efficiently and break down prematurely, it can lead to haemolytic anaemia — a type of anaemia caused by the shortened survival of red blood cells. 

For further information on unusual haemoglobins and the services we offer, please get in touch with our team. 

Rare red cell anaemias are uncommon inherited or acquired disorders that affect the production, structure, or function of red blood cells, often leading to anaemia. These conditions typically disrupt the body’s ability to produce healthy red blood cells, which are responsible for transporting oxygen throughout the body.  

Here are some examples of rare red cell anaemias: 

1. Diamond-Blackfan anaemia (DBA): an inherited bone marrow disorder that impairs red blood cell production, leading to severe anaemia. People with DBA often require blood transfusions or other medical interventions and may have other congenital anomalies. 

2. Fanconi anaemia (FA): a genetic disorder that affects bone marrow, resulting in decreased production of all blood cell types, including red blood cells. FA can lead to aplastic anaemia, a condition where bone marrow fails to produce sufficient blood cells, and it increases the risk of cancers and physical abnormalities. 

3. Congenital Dyserythropoietic anaemias (CDAs): a group of inherited disorders characterised by abnormal red blood cell development in the bone marrow. CDAs lead to various degrees of anaemia, and some patients may require blood transfusions. Different types of CDAs are classified based on genetic mutations and cellular characteristics. 

4. Sideroblastic anaemia: a group of disorders where the bone marrow produces ringed sideroblasts (abnormal red blood cells with iron-laden mitochondria) instead of healthy red cells. This can lead to a form of anaemia that does not respond well to iron supplementation and may require other treatments. 

5. Pyruvate Kinase deficiency: a genetic disorder affecting the enzyme pyruvate kinase, which is essential for red blood cell energy production. Without adequate energy, red blood cells break down prematurely, leading to haemolytic anaemia, where red blood cells are destroyed faster than they are produced. 

6. Thrombotic Thrombocytopenic Purpura (TTP): while not strictly a red cell disorder, TTP is a rare blood disorder where blood clots form in small blood vessels throughout the body, leading to the destruction of red blood cells. This results in anaemia, low platelets, and, in severe cases, organ damage. 

7. Paroxysmal Nocturnal Haemoglobinuria (PNH): a rare disorder which develops after birth where red blood cells are abnormally sensitive to the body’s immune system, causing them to break down prematurely. PNH leads to haemolytic anaemia, fatigue, and an increased risk of blood clots. 

These rare anaemias can have varying degrees of severity and may require specialised treatments, including blood transfusions, medications, or, in some cases, bone marrow transplantation.  

Early diagnosis and expert management are essential to help reduce complications and improve quality of life for individuals with these conditions.