What is it?Sickle cell anaemia is an inherited genetic conditionSickle cell anaemia is an inherited genetic condition in which there's an abnormality in haemoglobin, the oxygen-carrying protein found in red blood cells.People with sickle cell anaemia have a type of haemoglobin known as sickle haemoglobin (HbS), which is different from normal haemoglobin (HbA).Normal red blood cells can bend and flex easily, and so travel around the blood vessels easily. 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.They are then less able to squeeze through small blood vessels. These small blood vessels easily become blocked, preventing oxygen from getting through and causing severe pain and damage to organs.What are the symptoms? Blockage of a blood vessel causes an attack known as a crisis. This is more likely to happen when the person is stressed by another illness, exhaustion, cold, dehydration and other problems.Organs such as the liver, kidney, lungs, heart and spleen become damaged, causing severe pain, especially in the bones. The red blood cells also break up easily, leading to anaemia.Who's affected? More than 12,500 people in the UK have sickle cell anaemia. The majority of them are of African or Caribbean descent, although it also affects those from Asia, the Middle East and the eastern Mediterranean.Sickle cell anaemia is an autosomal recessive genetic condition. Everyone has two copies of the haemoglobin gene, one from each parent. Those with sickle cell anaemia have two HbS genes. Those who have one HbA gene and one HbS gene are said to have sickle cell trait. There are 240,000 carriers of sickle cell anaemia and they're only at risk of problems under extreme conditions, such as during major surgery.How's it diagnosed? Testing during pregnancy, from 11 weeks and usually with CVS (chorionic villus sampling), can identify the haemoglobin type of the baby, while adults can easily be screened.What's the treatment? There's no cure for sickle cell anaemia, but the frequency and severity of crises and their complications can be reduced by prompt recognition and treatment.Bone marrow transplants have been used in some cases and, while it is still early days, the procedure holds promise for the future.Advice and support Sickle Cell Society Tel: 020 8961 7795 Email: info@sicklecellsociety.org Website: www.sicklecellsociety.orgThis article was last medically reviewed by Dr Rob Hicks in July 2006.Source: BBC Health