Sickle cell - the facts
World Sickle Cell Day was recently marked on 19th June. Among the most common inherited conditions in the UK today, it's more common in people of Afro-Caribbean, African, Mediterranean or Asian heritage.
We inherit two copies of every gene - one from each parent. If you have one sickle cell gene, you won't be affected by sickle cell disease but you have sickle cell trait. If you do have any symptoms, they're much milder than sickle cell disease, but you could pass the gene on to your children.
If you inherit a sickle cell gene from both parents (or one sickle cell gene and another related abnormal gene), you will be born with sickle cell disease. Your red blood cells, which contain a chemical called haemoglobin and deliver oxygen to your body's tissues, can change from their normal doughnut shape into a sickle or crescent shape. Symptoms don't usually start until you're three to six months old, but from then on you can get episodes of 'sickle crisis' from time to time. This happens when a lot of your red blood cells change to a sickle shape at the same time, causing blockage in blood vessels. The most common place for this to happen is in the small blood vessels in the bones and joints. Along with pain which comes on suddenly, there may be joint swelling. If blood vessels in the lungs are affected, the result can be breathlessness, fever and chest pain.
The commonest type of sickle cell disease is sickle cell anaemia, which affects people with two sickle cell genes. As the name suggests, one of the symptoms is anaemia, or low levels of haemoglobin . Like other forms of anaemia, such as iron deficiency anaemia seen in women with heavy periods, it can cause tiredness, breathlessness and dizziness.
Triggers for sickle cell crises include being dehydrated, generally unwell or cold. Infections can be more severe if you have sickle cell disease, and can also trigger a crisis. That's why daily antibiotics, along with regular immunisations against influenza, pneumococcus, meningitis and hepatitis B along with all the standard childhood immunisations, are recommended. So is a daily folic acid tablet, which helps the body produce red blood cells.
World Sickle Cell Day aims to raise awareness of the importance of regular medication and immunisations, and seeking help quickly for possible crises. But equally importantly, it's about alerting people to the possibility of passing on the sickle cell gene before they have children. Policies for screening for sickle cell trait for adults vary across the UK - in England, all babies are screened for sickle cell as part of routine screening tests within a week of birth .
It's possible to have sickle cell trait without ever knowing it, so the only way to know for certain is to be screened, ideally before you get pregnant. If you're found to carry a single sickle cell gene, the father of any baby you are planning will also be offered screening. If you both carry a single gene, there's a one in four chance that your baby will have sickle cell disease and a 1 in 2 chance that they'll have sickle cell trait. Your doctor can discuss what this means in terms of any future plans for pregnancy.
If you're tested in early pregnancy and it's found that your baby has a chance of inheriting sickle cell disease, your partner will also be tested. If he's also found to carry a gene, you'll be offered screening for your baby as soon as possible during pregnancy. This can be done through chorionic villus sampling or amniocentesis.
Burying your head in the sand where sickle cell disease is concerned isn't an option. Discovering you carry a sickle cell gene isn't good news - but it will let you make the best decisions for your baby.