What is Sickle Cell?

Sickle Cell or 'Sickle Cell Syndrome' is the name of a group of inherited diseases caused by a mutation in a blood protein called haemoglobin.

All sickle cell syndromes share one thing: structurally abnormal haemoglobin. Haemoglobin, which is a key component of red blood cells, is responsible for adequately delivering oxygen throughout the body and keeping red blood cells from deforming and losing function.

Sickle Cell Anaemia

Often when people discuss sickle cell disease, they're actually referring to sickle cell anaemia. In sickle cell anaemia, the gene for sickle haemoglobin is inherited from both parents and results in the production of only abnormal sickle haemoglobin.

The same sickling of red blood cells shows up in other forms of the disease as well. The most common are sickle haemoglobin C, often called "SC disease," and sickle beta Thalassaemia, or "sickle beta thal."

In sickle haemoglobin C disease, one parent passes down the gene for sickle haemoglobin, while the other parent contributes the gene for the abnormal C type of haemoglobin. The result is commonly referred to as HbSC.

Thalassaemia

Similarly, a child with sickle beta thal also has one gene that makes sickle haemoglobin. But the other half of the equation, the beta Thalassaemia gene, produces either poorly functioning haemoglobin or none at all. In this situation, the majority--if not all--of the resulting haemoglobin is sickle haemoglobin.

Sickle Cell Disease

So sickle cell disease results not only from the inheritance of two sickle haemoglobin genes, but also from one sickle haemoglobin gene combined with another abnormal haemoglobin gene.

'Sickling'

The sickle cell mutation leads to changes in the shape and behaviour of red blood cells. The clinical picture of patients with sickle cell syndrome can be remarkably different. Some patients remain virtually without complaints, while others suffer repeated or near permanent episodes requiring admission to hospital from early childhood. The red blood cells affected, 'sickle' i.e. become hard, sticky and misshaped, often in the form of a sickle (the sharp hooked blades used to cut wheat). These distorted cells may cause small blood clots that block blood flow causing; repeated painful episodes called crisis, oxygen starvation to affected areas, strokes and other severe damage to the organs in the body.