Published January 2022
Contents
― Being a carrier
― Your baby
― Chances of inheriting a serious condition
― Inherited haemoglobin conditions
― Thalassaemia major
― Sickle cell disorder
― Next steps and choices
― Newborn Screening
― Other family members
― Future pregnancies
― How your test result is written
― More information
Being a carrier does not make you ill. You will not develop a haemoglobin condition that needs treatment but it is important to know that you can pass the delta beta thalassaemia gene on to your baby. If the baby’s biological father is also a carrier, together you could have a baby with a serious inherited condition. The chance is the same in every pregnancy.
Haemoglobin is the substance in red blood cells that carries oxygen around your body. Being a carrier means you have inherited one usual haemoglobin gene called haemoglobin A from one biological parent and one delta beta thalassaemia gene from your other biological parent. Because you have inherited haemoglobin A from one parent, you are healthy.
If your baby’s biological father has an unusual haemoglobin gene it is important to identify the type of gene and the chance of your baby inheriting a serious haemoglobin condition. For this reason, we will also invite the biological father for screening. He will only know if he carries a gene for unusual haemoglobin if he has a blood test to check his haemoglobin type.
If the test shows the biological father is a carrier of an unusual haemoglobin gene you will be offered specialist counselling and, if necessary, invasive testing.
Please let your healthcare professional know if you:
There are a number of different haemoglobin conditions your baby could inherit. Some are more serious than others. The type and severity of the condition depends on the types of haemoglobin genes you and your baby’s biological father have.
The most serious conditions are thalassaemia major and sickle cell disorder. People who have thalassaemia major or sickle cell disorder need specialist care and treatment throughout their lives.
One biological parent is a carrier and the other is not
If your baby’s biological father has two usual haemoglobin genes (AA), there is a 2 in 4 (50%) chance your baby will be a delta beta thalassaemia carrier (like you) and a 2 in 4 (50%) chance they will have two usual haemoglobin genes (AA).
See diagram below. These chances are the same in every pregnancy for this couple.
Both biological parents are carriers
If the baby’s biological father is also a carrier, there is a 1 in 4 (25%) chance your baby will inherit a haemoglobin condition. The seriousness of the condition will depend on what haemoglobin genes are inherited.
There is also a 2 in 4 (50%) chance your baby will be a carrier, and a 1 in 4 (25%) chance your baby will have usual haemoglobin genes (AA).
See diagram below. These chances are the same in every pregnancy for this couple.
Haemoglobin conditions are blood disorders inherited from both biological parents.
There are a number of haemoglobin conditions, but the type of condition your baby could inherit will depend on what types of haemoglobin genes both biological parents have. Some conditions are more serious than others.
The most serious conditions are called thalassaemia major and sickle cell disorder. People who have these conditions will need specialist care and treatment throughout their lives.
If your baby’s biological father is a beta thalassaemia carrier there is a 1 in 4 (25%) chance that your baby could inherit thalassaemia major (the specific condition is beta thalassaemia/delta beta thalassaemia). This can either be a serious condition that requires specialist care and treatment, or a mild condition that only occasionally requires treatment. Your healthcare professional will be able to explain this to you in more detail. There is also a 2 in 4 (50%) chance your baby could be a carrier, or a 1 in 4 (25%) chance that your baby could have the usual haemoglobin AA
If your baby’s biological father is a sickle cell carrier, there is a 1 in 4 (25%) chance that your baby could inherit sickle cell disorder. This is a condition that requires specialist care and treatment.
If your baby’s biological father carries the gene for a different unusual haemoglobin, for example haemoglobin E, delta beta thalassaemia or haemoglobin Lepore, there is a 1 in 4 (25%) chance that your child could inherit a different haemoglobin condition. The seriousness of the condition will depend on which genes are inherited. You can discuss this with your health professional, so that you understand exactly what condition your baby could inherit.
People with thalassaemia major:
People with sickle cell disorder have red blood cells that can become misshapen when they release oxygen around the body. This can block small blood vessels.
People with sickle cell disorder:
If screening shows your baby could inherit a serious haemoglobin condition you will be offered specialist counselling and invasive testing.
All babies are offered a newborn blood spot screening test five days after their birth. This test will screen for sickle cell disorder.
You can also:
As you are a delta beta thalassaemia carrier, other members of your biological family could be carriers too.
We recommend you talk to your parents, brothers, sisters, uncles, aunts and cousins, and encourage them to get a test before they start a family or have any more children. Showing them this information may help.
It is equally important for men and women to be tested. Anyone can ask for a test at any time from their GP or from a specialist sickle cell thalaessamia centre.
We recommend you tell your healthcare professional about your carrier status as early as possible in any future pregnancies.
It is important to test the baby’s biological father and be referred to a specialist counsellor.
As a delta beta thalassaemia carrier your screening result is written delta beta (δβ) thalassaemia carrier. ‘δ’ is the Greek letter delta and ‘β’ is the Greek letter beta.
You can get more information from the following.
https://111.wales.nhs.uk/encyclopaedia/t/article/thalassaemia/