; What is Sickle Cell Anaemia
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What is Sickle Cell Anaemia

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									Gene Mutation What is Sickle Cell Anaemia?
The disorder affects the red blood cells which contain a special protein called haemoglobin (Hb for short). The function of haemoglobin is to carry oxygen from the lungs to all parts of the body.
People with Sickle Cell Anaemia have Sickle haemoglobin (HbS) which is different from the normal haemoglobin (HbA). When sickle haemoglobin gives up its oxygen to the tissues, it sticks together to form long rods inside the red blood cells making these cells rigid and sickle-shaped. Normal red blood cells can bend and flex easily Because of their shape, ‘sickled’ red blood cells can't squeeze through small blood vessels as easily as the almost donut-shaped normal cells. This can lead to these small blood vessels getting blocked which then stops the oxygen from getting through to where it is needed. This in turn can lead to severe pain and damage to organs.

Normal red blood cells

‘ sickle’ shape of cells causes them to clump together.

Everyone has two copies of the gene for haemoglobin; one from their mother and one from their father. If one of these genes carries the instructions to make sickle haemoglobin (HbS) and the other carries the instructions to make normal haemoglobin (HbA) then the person has Sickle Cell Trait and is a carrier of the sickle haemoglobin gene. This means that this person has enough normal haemoglobin in their red blood cells to keep the cells flexible and they don't have the symptoms of the sickle cell disorders. They do however have to be careful when doing things where there is less oxygen than normal such as scuba diving, activities at high altitude and under general anaesthetics. If both copies of the haemoglobin gene carry instructions to make sickle haemoglobin then this will be the only type of haemoglobin they can make and sickled cells can occur. These people have Sickle Cell Anaemia and can suffer from anaemia and severe pain. These severe attacks are known as Crises. Over time Sickle Cell sufferers can experience damage to organs such as liver, kidney, lungs, heart and spleen. Death can be a result.

Other types of Sickle Cell Disorders (SCDs)
There are also other different types of haemoglobin such as HbC and beta thalassaemia, that can combine with sickle haemoglobin to cause sickling disorders. When someone carries the gene for beta-thalassaemia they cannot make as much HbA as they should. If this is combined with the HbS gene then more of their total amount of haemoglobin is HbS and they can suffer from what is usually a milder form of sickle cell disorder than sickle cell anaemia.

Who Gets SCDs?
The different kinds of SCD and the different traits are found mainly in people whose families come from Africa, the Caribbean, the Eastern Mediterranean, Middle East and Asia.* In Britain SCD is most common in

people of African and Caribbean descent (at least 1 in 10-40 have sickle cell trait and 1 in 60-200 have SCD). It is estimated there are over 6,000 adults and children with SCD in Britain at present. There are other inherited conditions that mainly affect other groups, e.g. Cystic Fibrosis in Europeans, and Tay-Sachs disease in Jewish people.

Testing for SCDs
A special blood test (haemoglobin electrophoresis) can tell you whether you have a sickle cell disorder or are a healthy carrier, e.g. for sickle cell trait. Routine screening should take place for people in the groups listed during pregnancy and before anaesthesia, either at hospital or dental clinics.

What Sickle Cell Disorders are Not
People are often confused and disturbed by some of the incorrect information they have received about SCD. Sickle Cell Disorders are not leukaemia are not cancer are not white blood cells eating up red blood cells are not infectious - you cannot `catch it' as you would catch measles or a cold. Sickle Cell Disorder is a condition that is inherited from both parents. This means that people are born with it, just as they are born with other characteristics such as eye colour, hair texture and height. www.sicklecellsociety.org


								
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