Sickle Cell Traits and Carriers
If you're a carrier of sickle cell, it means you carry one of the genes that causes sickle cell disease, but you do not have the condition yourself. It's also known as having the sickle cell trait. People who carry sickle cell will not develop sickle cell disease, but may be at risk of having a child with sickle cell disease and may occasionally need to take precautions to stop them becoming unwell.
Who can be a sickle cell carrier?
Anyone can be a carrier of sickle cell, but it's much more common in people from certain ethnic backgrounds.
In the UK, most people who carry the sickle cell trait have an African or Caribbean family background.
Testing for sickle cell carriers
You can find out if you're a carrier of sickle cell by having a simple blood test.
Screening for sickle cell disease is offered to all pregnant women in England, although most women will be at low risk and will not need to have a blood test to check if they're a carrier.
GOV.UK has detailed information about being a sickle cell carrier.
Anyone can ask to have a free blood test to find out if they're a carrier at any point.
This can be useful if:
- you want to find out if you're at risk of having a child with sickle cell disease
- you have a family history of sickle cell disease or carrying the sickle cell trait
- your partner carries the sickle cell trait
You can request the test from your GP surgery or nearest genetic counsellor, who'll discuss the result and implications with you if you're found to carry sickle cell.
If you carry the sickle cell trait, you're at risk of having children with sickle cell disease, although this can only happen if your partner is also a carrier or has sickle cell disease themselves.
If you're planning to have a child and you know you're a carrier, it's a good idea for your partner to be tested.
If you and your partner both carry sickle cell, there's a:
- 1 in 4 chance each child you have will not have sickle cell disease or be a carrier
- 1 in 2 chance each child you have will be a carrier, but will not have sickle cell disease
- 1 in 4 chance each child you have will be born with sickle cell disease
If both of you are carriers and you're planning to have a baby, talk to your GP about getting a referral to a genetic counsellor, who can explain the risks to your children and what your options are.
- having tests during pregnancy to see if your baby will have sickle cell disease
- adopting a child
- trying IVF with a donor egg or sperm
- trying pre-implantation genetic diagnosis (PGD)
PGD is a treatment used in IVF where the resulting embryos are tested to check that they do not have sickle cell disease before they're implanted in the womb.
The Human Fertilisation and Embryology Authority (HFEA) has more information about PGD.
Screening for sickle cell and thalassaemia
Sickle cell disease (SCD) and thalassaemia are inherited blood disorders.
If you're a carrier of the sickle cell or thalassaemia gene, you can pass these health conditions on to your baby.
All pregnant women in England are offered a blood test to find out if they carry a gene for thalassaemia.
Those at high risk of being a sickle cell carrier are offered a test for sickle cell.
If the mother is found to be a carrier, screening is also offered to the father.
This test should be offered before you're 10 weeks pregnant. It's important the test is done early.
If you find out you're a carrier, you and your partner will have the option of further tests to know if your baby will be affected.
Why could I be offered screening for sickle cell and thalassaemia early in pregnancy?
Screening is offered to find out if you're a carrier of a gene for sickle cell or thalassaemia and therefore likely to pass it on to your baby.
Genes are the codes in our bodies for things like eye colour and blood group.
Genes work in pairs: for everything we inherit, we get 1 gene from our mother and 1 gene from our father.
People only have sickle cell disease or thalassaemia if they inherit 2 unusual haemoglobin genes: 1 from their mother and 1 from their father.
People who inherit just 1 unusual gene are known as carriers or as having a trait.
Carriers are healthy and do not have the disease.
Sickle cell carriers can experience some problems in situations where their bodies might not get enough oxygen, such as having a general anaesthetic.
All carriers can pass the unusual gene on to their children.
When both parents are carriers
When both parents are carriers, each time they're expecting a child there's:
- a 1 in 4 chance of the child not having or carrying the disease
- a 2 in 4 chance of the child being a carrier
- a 1 in 4 chance of the child having the disease
Anyone can be a carrier of haemoglobin disease. But it's more common among people with ancestors from Africa, the Caribbean, the Mediterranean, India, Pakistan, south and southeast Asia, and the Middle East.
Read more about being a carrier of sickle cell disease or a carrier of thalassaemia.
Rare health risks
You're not at risk of developing sickle cell disease if you carry the sickle cell trait.
The only time you may be at risk of health problems is in rare cases where you might not get enough oxygen, such as:
- having surgery under general anaesthetic – make sure medical staff are aware you carry the sickle cell trait before your operation
- during regular intensive physical activity – make sure you drink plenty of fluids during training and avoid extreme exhaustion
- There's also a very small risk of developing kidney problems associated with carrying sickle cell.
Apart from these uncommon situations, you can lead a completely normal and healthy life if you're a sickle cell carrier.
People who carry other blood disorders
People who are carriers of the sickle cell trait are also at risk of having a child with a blood disorder if their partner is a carrier of a different type of blood disorder.
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