Hello again from the UK Thalassaemia Society! In the last issue, we explained what thalassaemia is, how it affects the body and how it is treated. As you may remember, thalassaemia is a genetic condition which is present at birth – in the last article we promised a full explanation of the inheritance pattern, so here goes!
It works like this. Thalassaemia carriers are completely healthy, but they carry an unusual gene which may be passed on to their children. If a child inherits this unusual gene from one parent, it does not cause any medical problems – it simply means that the child will be, like its parent, a healthy carrier. The problem arises where a man and woman who are both carriers have a child. If the child inherits two unusual genes – one from each parent – that child will not be able to manufacture fully functioning red blood cells; and will be born with thalassaemia. Below is a diagram showing how thalassaemia is inherited.
It is important to remember that the risk is the same in every pregnancy and whether the child will be affected is totally random. If a couple at risk had, for example, 10 children, they might all be healthy or they could all have thalassaemia – or, which is more likely, they could have a mixture of healthy and affected children.
Who is at risk?
Anyone can be a carrier of thalassaemia, but you could be at increased risk if you have family origins in the Middle East, the Far East, the Southern Mediterranean or anywhere on the Indian subcontinent. UKTS strongly recommends that everyone whose family comes from the higher risk areas should be tested for the thalassaemia gene before having children. If you know you carry the gene, you can ask your partner to be tested – if your partner is clear there is no risk to your children; but if you are both carriers you can at least learn all about thalassaemia and discuss the issue thoroughly with each other before you have children. When we talk to young people about having a test before they have children, they often tell us something like, “Oh there’s no need – there’s no illness in our family”. But virtually all the parents we hear from who have babies born with thalassaemia tell us the same thing – “There’s never been anything like this in our family, we had no idea we were at risk.” It is precisely because carriers of thalassaemia are healthy and have no symptoms that the condition can remain hidden for generations, passed down from parent to child, with no-one having any idea it is there at all – until the time comes when one of the family members happens to meet another person who is a carrier and an affected child is born. So please – don’t let the birth of a baby with thalassaemia be the wake-up call for your family – get tested!
How can I get tested?
The only way to tell whether you are a carrier of thalassaemia is by a specific blood test called a haemoglobinopathy screen. There is no other way to be sure. (Do not assume that thalassaemia would have “shown up” in a blood test done for some other reason; it must be a specific test.) The test is available from your GP and can be done at any age. If you have any problem in arranging a test, please contact us at UKTS and we can advise you where you can arrange a test.
You can ask your GP to test you at any time – please contact UKTS for more information on testing or for free advice and information about thalassaemia.